INTRODUCTION dislodgement along the path of insertion’.[3,4] Thus
INTRODUCTION Retention in denture is a subject which perplexes and perpetual until it finds a better understanding in science.1 This leads to a fact which exists but in repetition of enormous beliefs. Although their affaires and context have been accounted in detail and discussed at various articles , all the previous and recent account have been based on advance research and thus understanding the materials of science which is yet to be appeared in an more accessible form for all the practitioners throughout the world . Thus this articles main aim is to address this default. Denture retention has been defined as ‘resistance of a denture to vertical movement away from the tissues’2 and as ‘that quality inherent in the prosthesis acting to resist the forces of dislodgement along the path of insertion’.3,4 Thus it is understood that the retention is regarded as one the factor of the denture rather than of the patient. There is an overall approval mostly among all the practitioners to achieve retention in complete dentures and cast partial denture which first needs an accurate fit of denture base to that of the mucosa in order to provide a minimal gap between them. Further, the borders of the denture should have a accurate seal which can be accomplished by futher lenghtening the denture flanges in order to reach the sulci. The content of this article is mainly to achieve physical retention to the dentures using the vibrating lines. There are various factors involving in denture retention such as atmospheric pressure, vacuum, adhesion, cohesion, wettability, surface roughness, gravity, surface tension, viscosity, base adaptation, border seal and muscular control which all play an lethal role in forming the seal in denture. Although, these various factors have perceived for a majority of time in several textbooks, articles and researches but they all do not survive scientific survillance.5,6 Retention is an imported factor required for both complete denture and cast partial denture which can be withheld against the force acted by gravity. Retention of denture can be obtained by various methods. One of the convenient method is by locating the position of the posterior border of denture in maxilla, which can play a vital role in obtaining retention and also can provide patient comfort. For many centuries, researchers have estimated many techniques in determine the ideal location of the posterior border of the maxillary denture. The commonest method is by using anatomical land marks . 7,8 Fovea palatinae is considered as one of the anatomical landmark of maxilla which provides a reliable guidelines for the placement of the posterior palatal seal. There is a known controversy which describes about the relationship of fovea palatinae briefing that fovea palatinae are situated either anterior or posterior to the anterior vibrating lines and it situated anteriorly to the posterior vibrating line.9,10,11 The fovea palatinae is seen as two small indentation which lie on the either side of the midline of the palate approximating the junction between the soft and hard palate. Thus they signify the sites of opening of ducts of small mucous glands present in the palate.12 Post palatal seal is also one the anatomical landmark of maxilla which plays a major role in proving retention of maxillary dentures. It is a soft tissue area present at or beyond the junction of the hard and soft palates.It is also considered to lie between anterior and posterior vibrating line.13 Anterior vibrating line is known as an imaginary line situated at the junction between the attached tissue overlying the hard palate and the movable tissue of the soft palate, which can be anticipated by making the patient to say ‘;ah’ with short vigorous bursts. Posterior vibrating line is also another imaginary line which is present at the junction of the aponeurosis of the tensor veli palatine muscle and the muscular portion of the soft palate which can be anticipated by making the patient to say ‘ah’ in short bursts in a normal unexaggerated fashion. Although the vibrating lines is not considered as a true anatomical features, but it is very important feature which acts as a guidance in proper construction of the maxillary complete denture and also cast partial denture.9,12,14In one such study,the distance between the anterior and posterior vibrating lines was found to be 2 and 8 mm 9,15 .The distance between the foveae palatinae and the vibrating line can alter according to the various configuration of the soft palate; hence in a soft palate with has a less steep slope could be expected to be longer, which implys that a broader posterior palatal seal could be accomplished .16,17The purpose of this study is using fovea palatinae as reference point for locating both anterior and posterior vibrating lines.