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.     

A provisional and new crown to fit into a clasp of an existing removable partial denture

A technique that forms an abutment crown to fit into an existing clasp of a removable partial denture by relining an acrylic resin pattern is described. The outer contour of the pattern is made within an irreversible hydrocolloid impression by use of Duralay autopolymerizing acrylic resin applied with precision dispensers. The pattern is formed before tooth preparation and is made approximately 0.4 mm thick. After tooth preparation, the shell pattern is relined with the same autopolymerizing resin and the existing removable partial denture is fitted over it. The gross pattern is trimmed and the margins refined on a die made from an elastomer impression. The refined pattern is cast and finished, avoiding reduction of the contours established. A second crown is similarly formed in tooth-colored autopolymerizing acrylic resin. It serves as a provisional restoration that allows the patient to wear the removable partial denture while the laboratory procedures are performed.     

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.     

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.     

Fabricating crowns to fit clasp-bearing abutment teeth

As with other direct-indirect methods, the Duralay index method has the advantage of not depriving patients of their dentures. The index takes very little time to fabricate since it is only necessary to obtain a Duralay mold of the internal surface of the clasp assembly and the external surface of the prepared tooth. In addition, the index will serve as a guide for the final waxup. In waxing, it will only be necessary to fill in the contours and margins without touching the index surfaces which contact the clasp assembly and occlusal stops. If occlusal stops were incorporated in the index, no opposing cast is necessary. This method may be used with full veneer and veneered crowns and any impression technique and die material providing that the expansion during investing and casting results in a passive fit of the crown.     

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.     

The fit of fixed partial dentures joined by infrared soldering.

This study determined the accuracy of fit of three-unit fixed partial dentures joined by an infrared soldering technique compared with one-piece fixed partial denture castings and individually cast crowns. Wax patterns of prepared Ivorine teeth, maxillary left central incisor and maxillary left canine, were injection molded; a plastic rod was used as a pontic. One group of patterns was cast as one-piece dentures; the other group was sectioned in the connector area, cast individually and then joined by infrared soldering. Castings were seated on their respective dies, embedded in epoxy resin, and sectioned. Gap distances between the casting and the die were measured at specified marginal sites with a profile projector. Results showed that the fit of infrared-soldered fixed partial dentures was significantly better than that of one-piece castings and was comparable with the fit of single crowns. The gap openings measured in all castings were within the range of clinical acceptability.     

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.     

Fabrication of a crown to fit an existing partial denture using castable glass

In this case report, an accepted technique was used to fabricate a crown to fit an existing removable partial denture in which castable glass was used instead of gold. The use of castable glass allowed the crown to be cast directly from a wax-acrylic pattern and eliminated the need for templates to produce accurate facial contours in porcelain. Although castable glass has limitations and cannot be used in all such situations, the material can be used in selected cases where esthetics is important.     

The Use of CAD/CAM Technology for Fabricating Cast Gold Survey Crowns under Existing Partial Removable Dental Prosthesis. A Clinical Report

The fabrication of a survey crown under an existing partial removable dental prosthesis (PRDP) has always been a challenge to many dental practitioners. This clinical report presents a technique for fabricating accurate cast gold survey crowns to fit existing PRDPs using CAD/CAM technology. The report describes a technique that would digitally scan the coronal anatomy of a cast gold survey crown and an abutment tooth under existing PRDPs planned for restoration, prior to any preparation. The information is stored in the digital software where all the coronal anatomical details are preserved without any modifications. The scanned designs are then applied to the scanned teeth preparations, sent to the milling machine and milled into full‐contour clear acrylic resin burn‐out patterns. The acrylic resin patterns are tried in the patient's mouth the same day to verify the full seating of the PRDP components. The patterns are then invested and cast into gold crowns and cemented in the conventional manner.     

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。     

牙科激光焊钛固定桥适合性的研究

目的:比较整体铸造钛固定桥与分部铸造后激光焊接钛固定桥的适合性。方法:机械加工2个标准金属全冠模型,用硅橡胶制取阴模并灌注13个超硬石膏模型。浸蜡压塑成形法完成统一规格的蜡型,桥体用同一规格的塑料棒代替。共分为3组,即单冠铸钛组、分部铸钛焊接组、整体铸钛组。铸件完成后分别置于各自的石膏代型上,用环氧树脂包埋、片切,在HitachiS-2700扫描电子显微镜下观察颈缘特定位置铸件与代型之间的间隙。结果:整体铸钛组颈缘间隙明显大于分部铸钛焊接组和单冠铸钛组(P<0.05),分部铸钛焊接组和单冠铸钛组的颈缘间隙无明显区别。结论:分部铸钛焊接组的适合性优于整体铸钛组。3单位整体铸钛组的颈缘间隙小于100μm,也符合临床要求。     

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.     

Interocclusal wax impressions for use in provisional and associated fixed prosthodontic procedures

A procedure is presented for the construction of a direct provisional acrylic resin restoration by means of an interocclusal wax impression. This technique requires no preparation or laboratory time and quickly results in a restoration that accurately covers all margins of the preparation and restores proper contact, contour, and occlusion. This procedure can also be used for large restorations, immediate fixed partial dentures, final impressions of preparations, provisional crowns to fit existing removable partial dentures, and some office emergencies.     

Stress distribution of abutments and base displacement with precision attachment- and telescopic crown-retained removable partial dentures

Five types of removable partial dentures (two attachment dentures, two telescopic dentures and one clasp denture) were designed. The two attachment dentures were retained by the rigid-precision attachments with or without a stabilizing arm, and the two telescope dentures were retained with cone telescope crowns with or without cross-arch stabilization. The stresses acting on abutment teeth and denture bases and the movements of denture bases were investigated, and the influences of denture design were clarified. The stress acting on a terminal abutment tooth retained by a rigid-precision attachment or cone telescopic crown was larger than that acting on a terminal abutment tooth retained by a clasp. The attachment dentures tended to concentrate more stress at the terminal abutment tooth than did the telescopic dentures. The stress of denture base of an attachment denture and a telescopic denture was less than that of a clasp denture. There was no difference between the stresses of attachment and telescopic dentures. The displacement of the denture base tended to be less when the denture was designed with a rigid connection for the retainer and with cross-arch stabilization.     

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。     

Clinical management of abutments with intracoronal attachments.

A method of preparing teeth to accommodate intracoronal attachments is presented. The resulting prosthesis incorporates a fixed partial denture with physiologically contoured crowns and a removable partial denture with a precisely determined path of insertion. These techniques stress the importance of surveyed diagnostic casts and coordinated tooth preparations for artificial crowns to facilitate treating complex cases.     

Technique for making a template for temporary restorations

A fast, accurate, and simple technique for fabricating custom templates used to construct customized acrylic resin temporary crowns and fixed partial dentures has been presented. Acrylic resins are used directly on the diagnostic cast to restore single tooth contours, secure pontics to the cast, and to contour edentulous areas. Duplicate casts and impressions are not needed. Acrylic resins prove superior to wax and other materials for constructing custom templates because they will not distort or melt under the heat and pressure of the thermal vacuum machine. Thus, the template is accurate and free of melted residue on the inner template surface.     

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.