Fabrication of a New Crown and Provisional to an Existing Removable Partial Denture

A method of fabricating a new crown to an existing removable partial denture is described. A press-form plastic shell made from the diagnostic cast provides the outer contours for the abutment tooth, while an acrylic resin coping is fabricated on a die to provide accurate internal adaptation. The acrylic resin coping is seated on the prepared abutment. Autopolymerizing acrylic resin is mixed and placed in the plastic shell that is then placed in the mouth over the coping, forming the acrylic resin crown pattern. The removable partial prosthesis is fitted over the crown pattern intraorally. The pattern is transferred back to the die, the margins are refined, and the casting is completed and finished, avoiding reduction of the established contours. The same plastic shell is used with tooth-shaded acrylic resin to construct a provisional crown directly in the mouth. This technique allows the patient to wear the removable partial denture while the laboratory procedures are completed.     

Provisional restoration for abutment of an existing removable partial denture

The abutment of an existing removable partial denture may require a crown restoration. Fabrication of a provisional restoration to fit the existing clasp assembly requires special consideration. This article presents a simple technique for fabrication of such provisional restorations. An alginate impression is made of the arch with the removable partial denture in place. The abutment tooth is then prepared, providing adequate clearance between the clasp assembly and the tooth preparation. Cold curing acrylic resin of proper shade is mixed and poured in the impression of the abutment tooth. The impression is then seated in the mouth and removed before the acrylic resin is completely polymerized. The provisional restoration is then separated from the partial denture, finished and polished.     

Fabricating Crowns to Fit Existing Removable Partial Dentures: An Illustration of Two Techniques

The prosthetic treatment of a structurally compromised abutment tooth supporting a removable partial denture may present a variety of restorative modalities. Ideally, a surveyed crown is made for the individual tooth, which is later followed by a new removable partial denture fit to the contours of the crown. Frequently, however, the removable partial denture is clinically acceptable, and remaking the prosthesis is not indicated. In these cases, the crown can be made to fit the existing removable partial denture. Fabricating crowns to fit existing removable partial dentures can be accomplished using a direct method, an indirect method, or combinations of these techniques. Direct techniques traditionally use acrylic resin and inlay wax intraorally to develop a custom pattern that captures the contours of the clasp assembly. Indirect techniques use a pick-up impression to allow the crown pattern to be waxed against the denture framework on a cast in the laboratory. Combination methods use either a direct-indirect or indirect-direct approach. The direct-indirect method develops the preliminary resin pattern directly on the tooth and finalizes the contours in wax on a master cast. The indirect-direct technique initiates a crown pattern on a die and completes it either intraorally or on the die after the intraoral refinements. This article reviews the literature for methods of fabricating surveyed crowns under existing removable partial dentures. Additionally, two cases are presented that illustrate an indirect and combination direct-indirect technique for making the restorations.     

Laboratory procedures for the maintenance of a removable partial overdenture

Laboratory procedures in support of maintenance therapy for a typical patient with a removable partial overdenture were described. These procedures consisted of the fabrication of a gold metal coping and the reline of the prosthesis with autopolymerizing acrylic resin. In designing the coping contours, the technician must consider the path of insertion of the prosthesis and the space requirement for the overlying resin tooth. Reproduction of the dowel preparation is facilitated by using a plastic dowel as part of the coping wax pattern. The removable partial overdenture was relined with autopolymerizing acrylic resin in a reline jig. Tooth-colored acrylic resin was used in the concavity formed by the overdenture abutment to enhance esthetics. The requirement of a coordinated effort between the dentist and the dental laboratory technician is critical to the successful treatment of the removable partial overdenture patient.     

Acrylic resin blockout for interim removable partial dentures.

A technique using autopolymerizing acrylic resin as a blockout material has been described. This technique greatly simplifies the laboratory construction and insertion phases of the complex interim removable partial denture. It is not suggested that the acrylic blockout replace the wax blockout if a heat-cured denture base is not indicated. Wax should be used if a "sprinkle-on" autopolymerizing acrylic resin is used for the denture base.     

Acrylic resin removable partial dentures

An acrylic resin removable partial denture is distinguished from other types of removable partial dentures by an all-acrylic resin base which is, in principle, solely supported by the edentulous regions of the tooth arch and in the maxilla also by the hard palate. When compared to the other types of removable partial dentures, the acrylic resin removable partial denture has 3 favourable aspects: the economic aspect, its aesthetic quality and the ease with which it can be extended and adjusted. Disadvantages are an increased risk of caries developing, gingivitis, periodontal disease, denture stomatitis, alveolar bone reduction, tooth migration, triggering of the gag reflex and damage to the acrylic resin base. Present-day indications are ofa temporary or palliative nature or are motivated by economic factors. Special varieties of the acrylic resin removable partial denture are the spoon denture, the flexible denture fabricated of non-rigid acrylic resin, and the two-piece sectional denture. Furthermore, acrylic resin removable partial dentures can be supplied with clasps or reinforced by fibers or metal wires.     

Conversion of a removable partial denture to a transitional complete denture: a clinical report

A procedure is described for conversion of an existing removable partial denture into a complete denture using autopolymerizing tooth-colored acrylic resin, acrylic resin denture repair material, and a clear matrix template. The shape, color, and position of the lost natural teeth may be duplicated in the transitional denture, minimizing the psychological concerns of the patient regarding esthetics and social impact. Because the patient is never without teeth, an appropriate healing time can occur before fabrication of the definitive prosthesis.     

A technique for restoring abutments for removable partial dentures.

A technique was presented to restore a removable partial denture abutment so that the removable denture can continue to be used. The technique uses cold-curing acrylic resin in a rubber base impression form. The technique can be adapted to both direct and indirect procedures.     

Using Silicone Impression Material and Acrylic Resin to Fabricate Remount Casts for Removable Partial Dentures

A technique is described for fabrication of a remount cast for a removable partial denture. This procedure consists of filling the occlusal/incisal third with acrylic resin and injecting polyvinylsiloxane impression material into the irreversible hydrocolloid impression. This technique provides a simple method for making a remount cast and enables the clinician to remove and easily place the partial denture on the cast during occlusal refinement procedures without damage to the removable partial denture or the remount cast.     

Nontraumatic Final Impressions for Fixed Partial Dentures

A nontraumatic, nonretraction impression technique is presented which uses the fabrication of an acrylic resin shell from an interocclusal wax impression. A crucial step in the procedure is obtaining the complete finish line of the preparation within the resin. This tray, which is filled with an elastomeric impression material, is combined with a triple tray of the same material to provide all the necessary relationships to construct a crown or coping. This procedure is especially efficient for multiple abutments during fixed partial denture construction.     

The effect of tray selection on the accuracy of elastomeric impression materials

This study evaluated the accuracy of reproduction of stone casts made from impressions using different tray and impression materials. The tray materials used were an acrylic resin, a thermoplastic, and a plastic. The impression materials used were an additional silicone, a polyether, and a polysulfide. Impressions were made of a stainless steel master die that simulated crown preparations for a fixed partial denture and an acrylic resin model with cross-arch and anteroposterior landmarks in stainless steel that typify clinical intra-arch distances. Impressions of the fixed partial denture simulation were made with all three impression materials and all three tray types. Impressions of the cross-arch and anteroposterior landmarks were made by using all three tray types with only the addition reaction silicone impression material. Impressions were poured at 1 hour with a type IV dental stone. Data were analyzed by using ANOVA with a sample size of five. Results indicated that custom-made trays of acrylic resin and the thermoplastic material performed similarly regarding die accuracy and produced clinically acceptable casts. The stock plastic tray consistently produced casts with greater dimensional change than the two custom trays.     

Repair of a Removable Partial Denture Using Gold Occlusals

Limited interarch space causes maintenance problems with removable partial dentures. The problem of abrasion and breakage of acrylic resin teeth, the concomitant supraeruption of opposing natural teeth, and possible decrease of vertical dimension of occlusion can be prevented or minimized with cast-gold occlusals. Use of metal occlusals has been advocated on newly constructed removable partial dentures, but not on existing prostheses with severely worn or broken denture teeth. This article describes a repair procedure for a removable partial denture where minimal interarch distance resulted in wear and breakage of denture teeth. A thin, abraded denture tooth that had been repaired numerous times was prepared and covered with a cast gold restoration. The problem of abrasion and breakage of the acrylic resin tooth was solved and the service life of the prosthesis was extended.     

A combined analog and digital workflow for retrofitting a monolithic ceramic crown to an existing removable partial denture

A clinical and laboratory workflow for fabricating and retrofitting a monolithic ceramic crown to an existing removable partial denture (RPD) is described. A conventional polyvinyl siloxane impression was made of the prepared tooth with the RPD in place. A stone cast was poured and, after die sectioning, scanned with a tabletop scanner. The ceramic crown was designed and fabricated by using a digital workflow to fit the RPD clasp assembly, providing an adequate undercut for the clasp. The crown was then delivered and the RPD evaluated for adequate fit.     

Construction of a crown to fit a removable partial denture clasp.

This technique allows an accurate cast to be made of a prepared abutment tooth with the removable partial denture in place in the mouth. The partial denture is carefully removed from the cast, the crown waxed up, and the removable partial denture re-placed as many times as necessary during wax-up to obtain a crown that accurately fits the clasp.     

Functional impressions with thermoplastic materials for reline procedures

Used as an impression material in a reline or rebase technique for a new or existing distal extension mandibular removable partial denture or mandibular complete denture, thermoplastic resin provides a denture base with uniform support under an occlusal load and a smooth nonirritating acrylic resin surface.     

A procedure for fitting a fixed partial denture to an existing removable partial denture

An indirect technique for fitting a new cast gold crown or fixed partial denture (FPD) to an existing removable partial denture (RPD) is presented. This method uses an acrylic resin coping made on a definitive cast fit directly to the patient's RPD intraorally, with the new FPD subsequently completed on the cast. The patient does not have to relinquish the RPD for laboratory procedures, although an appointment is required to fit the coping intraorally where contact is made with the RPD.     

Bonding of plastic teeth to denture base resins.

This study evaluated the bond strengths of some new and traditional resin denture teeth and denture base resins. It included regular monolithic acrylic resin teeth (Bioform), monolithic acrylic resin-IPN teeth (Bioform IPN), and multilithic acrylic resin-composite resin teeth (Vivosit), with relatively new light-activated resin (Triad), conventional heat-cured resin (Lucitone 199), and autopolymerizing resin (Hygenic) denture base materials. The results of four-point flexure testing showed that the traditional materials gave the highest bond strength values. The autopolymerizing resin systems demonstrated interfacial failure with all resin denture teeth, showing that the common practice of treating teeth with the respective autopolymerizing monomer failed to produce adequate bond strength. Combinations of acrylic resin, IPN, and multilithic denture teeth with light-activated resins gave results calling for improvements in basic bonding system design, since interface debonding was prevalent. No failures occurred between the lap-ridge region of the multilithic tooth system and conventional heat-cured denture base resin.     

利用阻生智齿预备钛金属冠改善下颌义齿固位的应用观察

目的:利用阻生智齿增加下颌单颌总义齿固位力。方法:通过手术暴露下颌阻生智齿,在智齿冠上预备牙体,制作钛金属套冠将阻生齿牙冠形态转移至口腔中,从而把固位力不足的下颌单颌总义齿修复,转变成有正常基牙固位的可摘局部义齿修复。结果:通过3例利用埋伏阻生智齿接钛金属套冠,对下颌牙槽嵴严重吸患者的可摘局部义齿修复,经2～3年的临床观察,钛套冠固定良好,无松动,牙龈正常。可摘局部义齿固位良好。结论:利用埋伏阻生智齿接钛金属套冠,加强下颌牙槽嵴严重吸收可摘局部义齿固位力的效果明显。     

制作适合原有可摘局部义齿的基牙全冠的临床方法

目的：研究制作适合原有可摘局部义齿的基牙全冠的修复方法。方法：采取间接法制作基牙全冠，即在备牙后制取模型，并留下可摘局部义齿在技工室制作全冠。结果：做冠后，可摘局部义齿的支托与全冠紧密贴合，卡环固位良好，患者对修复效果表示满意。结论：对于需要制作基牙全冠的病例，应该依据基牙外形保存情况、牙列缺损部位的不同，选择最佳的修复方法。