J ournal club PRESENTED BY: DR. BRAJ ENDRA SINGH TOMAR PRESENTED BY: DR. G. S. CHANDU Title The Use of Injectable Polyvinylsiloxane as Medium for Border-Molding Denture Impressions Author(G. Roger Troendle and Karen B. Troendle) JProsthod 1992, I: 121-123 CONTENTS Terminologies Introduction Border moulding Materials Article Discussion References TERMINOLOGIES Border seal: the contact of the denture border with the underlying or adjacent tissues to prevent the passage of air or other substances. Border tissue movements: the action of the muscles and other tissues adjacent to the borders of a denture. Border molding :Border molding is the shaping of an impression material by the manipulation or action of tissues adjacent to the borders of an impression tray. INTRODUCTION Master impression is the one of most important step in the fabrication of a complete denture. It should record the denture bearing area to reproduce finer details and muscular peripheral tissues in function. It involves 3 steps- 1.border moulding/ peripheral tracing 2.tray preparation after border moulding 3.making wash impressionBORDER MOULDING Border moulding is the process by which the shape of the border of the tray is made to conform accurately to the contours of the buccal and labial vestibules (Bouchers). The shaping of the border areas of an impression tray by functional or manual manipulation of the tissue adjacent to the borders to duplicate the contour and size of the vestibule(GPT-99). Determining the extension of a prosthesis by using tissue function or manual manipulation of the tissues to shape the border areas of an impression material(GPT-99). OBJECTIVE To determine the contours, height and width of the borders of the completed dentureREFINING THE CUSTOM TRAY For border moulding to be carried out successfully, space must be created for border moulding material. Therefore, flanges of the custom tray should be reduced until they are 2mm short of the reflections. Customtray should be 2-3 mm thick, with a stepped handle to facilitate easy removal. The step should be of sufficient height to avoid distortion of upper and lower lip. Border moulding can be performed either in Sections/recording one part of the border at a time. Simultaneous recording of all of the border. REQUIREMENTS OF MATERIAL FOR SIMULTANEOUS MOULDING Should have sufficient strength to remain in position on the borders during loading. Allow some preshaping of borders without adhering to fingers. Should have proper setting time. Should retain adequate flow while the tray is seated in mouth. Should not cause displacement of vestibular tissues. BORDER MOULDING WITH POLYETHER An adhesive for polyether is placed on the borders covering both inside and outside of the border. Polyether material is mixed and introduced into plastic syringes slightly less catalyst is used. Material is syringed around the borders and preshaped with fingers moistened in cold water. Loaded tray is placed in mouth carefully. If insufficient material, then excess material from adjacent site is transferred with finger. Border movements are carried out. This is accomplished in ant. region by elevating lip and extending outward, downward and inward for maxillary and by lifting lip outward, upward and inward for mandibular border moulding. In buccal frenum region cheek is elevated and then pulled outward ,downward and inward and then moved backward and forward to simulate frenum movement in maxilla whereas cheek is lifted outward ,upward and inward and then moved backward and forward to simulate frenum movement in mandible . Anterior lingual flange is moulded by asking pt to protrude the tongue and then to push tongue against ant palate. Tongue protrusion also activates mylohyoid muscle which raises floor of the mouth. this determines slope of lingual flange in molar region. Distal end of lingual flange is moulded by again asking pt to protrude the tongue. This records activated superior constrictor muscle, which supports retromylohyoid curtain. Then pt is asked to open wide and move mandible side to side. When material is set, tray is removed carefully and examined. BORDER MOULDING WITH GREEN STICK COMPOUND Soften one end of a stick of green impression compound slowly over alcohol torch. Place the compound along the border of the dried trayin segments. Temper the compound by placing it briefly in a 140 degree F water bath.Reflect the cheek with a mouth mirror and position the tray and seat it in the patient's mouth and border movements are performed. When set, remove the tray, repeat the procedure.The compound should be rounded with no voids, be symmetrical in shape, and should not be glossy.If voids are present or the compound is glossy, add more compound, flame, temper, and repeat the procedure. Next, add compound to the border of the tray from the previously molded area. Evaluate the retention and stability of the border molded maxillary tray.The fully seated tray should resist dislodging forces applied to the handle in a downward direction in the anterior and premolar area. If the tray comes away easily by a direct pull, it has poor retention and may be underextended.Check the stability by applying a horizontal force with your fingers to the handle of the tray. Evaluate the stability of the border molded mandibular tray.With the tongue at rest, the tray should resist dislodging forces applied to the handle in a horizontal direction in the anterior and premolar areas. If the border molded final impression tray does not exhibit stability and retention at this time, the complete denture will not be stable or retentive. Corrections should be made before proceeding to the next step. MATERIALS The different material that can be used are: a. Green stick compound . b. Polyether impression technique. c. Autopolymersing acrylic resins. d. Polyvinyl siloxane The Use of Injectable Polyvinylsiloxane as Medium for Border-Molding Denture Impressions The technique described here does not vary in concept from the classical technique. The only difference between this technique and the classic technique is the material used to border-mold and wash the final impression. TECHNIQUE Make a custom tray on a cast made from an irreversible hydrocolloid impression. Evaluate the custom tray in the patient's mouth to ensure that it is short of the estimated periphery of the final prosthesis. With a no. 8 round bur in a straight handpiece, perforate the complete periphery of' the tray. Place adhesive on the labial flange of the tray.Place the tray in the mouth, and inject Kerr Stat B.R. (Kerr Manufacturing Company, Romulus, MI) arid mold the material to the peripheral musculature. If needed, excess material can be trimmed with a sharp 25 surgical blade after the material sets. The maxillary tray is molded in four segments, 1.the labial flange 2.right buccal flange 3.left buccal flange and 4.posterior palatal flange. The remainder of the tray is painted with adhesive. Then medium-viscosity polyvinylsiloxane impression material is injected in the tray, placed in the patient's mouth, and border-molded.ADVANTAGES More acceptable to both dentist and patients. Easy manipulation. Less time consuming.DISADVANTAGE Cost of the material. Area of impression should be absolutely dry for better flow of material. DISCUSSION This technique was presented for border-molding a custom tray with a quick-set, high-viscosity polyvinylsiloxane material (Stat B.R.; Kerr) and making a wash with a medium-viscosity polyvinylsiloxane impression material (Express; 3M Dental Products, St Paul, MN). The technique was described for a maxillary overdenture, but is useful for complete dentures, both upper and lower. The principle of activating the musculature at the periphery of the denture is the same as when using the classical technique with thermoplastic compound. However, the technique using the polyvinylsiloxane material is more acceptable to the patient and dentist REFERENCES Essentials of complete denture prosthodontics ,2nd edition, sheldon winkler. Syllabus of complete dentures, C.M.Heartwell. Bouchers Prosthodontic treatment for edentulous patients,11th edition. Complete Dentures: A Clinical Manual for the General Dental Practitioner, Hugh Devlin THANK YOU