|Year : 2019 | Volume
| Issue : 2 | Page : 108-111
Simple technique to fabricate a crown for abutment of an existing cast partial removable denture
Shefali Singla1, Amarpreet Kaur1, Manu Rathee2
1 Department of Prosthodontics, Dr. Harvansh Singh Judge Institute of Dental Sciences and Hospital, Panjab University, Chandigarh, Haryana, India
2 Department of Prosthodontics, Pt. BD Sharma University of Health Sciences, Rohtak, Haryana, India
|Date of Web Publication||30-Apr-2019|
Department of Prosthodontics, Dr. Harvansh Singh Judge Institute of Dental Sciences and Hospital, Panjab University, Chandigarh
Source of Support: None, Conflict of Interest: None
The requirement of full crown restoration for abutments of existing Cast partial removable denture is common. Retrofitting a crown to existing cast partial denture (CPD) clasps and guiding planes is a challenging task. Literature describes various direct, indirect, and direct-indirect techniques to overcome this dilemma. All these involve elaborate steps, necessitating refabrication of CPD or extended clinical adjustment time for ensuring a proper fit that is elusive in most cases and also patient has to do without CPD during laboratory procedure. The recent use of computer-aided design-computer-aided manufacture technology for this purpose is proving to be a promising but expensive option. A simple technique is presented here to generate a blueprint of required final contours to facilitate a fully contoured metal crown to fit under an existing CPD.
Keywords: Cast partial denture, rest seat, retrofitting crown
|How to cite this article:|
Singla S, Kaur A, Rathee M. Simple technique to fabricate a crown for abutment of an existing cast partial removable denture. Indian J Dent Sci 2019;11:108-11
|How to cite this URL:|
Singla S, Kaur A, Rathee M. Simple technique to fabricate a crown for abutment of an existing cast partial removable denture. Indian J Dent Sci [serial online] 2019 [cited 2019 May 25];11:108-11. Available from: http://www.ijds.in/text.asp?2019/11/2/108/257300
| Introduction|| |
The need of restoration in an existing abutment tooth in a cast partial removable denture is a common occurrence. If the restoration is extensive, endodontic treatment followed by crown is necessary. In such situations, the recreation of occlusal rest seat and axially contouring the crown in accordance with clasps and minor connector of an existing partial denture is a challenging job. Fitting the removable partial denture on newly made crown may require considerable time for chairside adjustments and cause inconvenience to the patients. Literature describes various techniques for retrofitting a new crown to an existing cast partial removable denture as direct, indirect, and direct-indirect. However, there are chances of error being introduced by clinician/technician during the elaborate steps, necessitating refabrication of cast partial denture (CPD) or extended clinical adjustment time for ensuring a proper fit that is elusive in most cases and also patient has to do without CPD during the laboratory procedure. The recent use of computer-aided design-computer-aided manufacture technology for this purpose is proving to be a promising but expensive option. A simple technique is presented here to fabricate a fully contoured metal crown to fit under an existing CPD.
| Case Report|| |
A 66-year-old male patient reported to the department of prosthodontics and crown and bridge at our institute for fabrication of crown for an endodontically treated 17 which served as a principle abutment for a Kennedy's Class III modification 2 CPD with a mesioocclusal rest in relation to 17, fabricated 5 years ago. The patient was satisfied with the functioning of the denture. Owing to decay, the amount of residual coronal tooth structure in 17 was not enough to support a crown. Hence, a post and core restoration followed by crown fabrication was planned. After taking consent from the patient, the post space was prepared followed by fabrication of custom made cast post and core which was cemented with glass ionomer luting cement (GC Fuji I, GC Europe N. V.) [Figure 1]a and [Figure 1]b. On a subsequent appointment, after tooth preparation for metal-ceramic crown, denture was placed intraorally to check adequate axial clearance for crown fabrication [Figure 2]. The impression was made in polyvinyl siloxane material (3M ESPE Soft Putty and Express Ultralight Body, 3M India) and a provisional restoration in tooth-colored acrylic (DPI Self cure Tooth Moulding powder, DPI India) was fabricated on the cast using the indirect technique of provisionalization. While fabricating the provisional restoration, when the resin was still in dough stage, the CPD was seated on the cast so as to obtain negative impression of the rest seat and contour the axial surfaces according to clasp. To achieve accurate fit, the rest seat in the temporary crown was relined intraorally by seating of CPD and patient's mouth closed in occlusion [Figure 3]a. Before cementing the provisional crown using zinc oxide eugenol cement (Temp-Bond, Kerr, America), a putty index [3M ESPE Soft putty [Figure 3]b of this restoration was made and was utilized for making full contoured wax pattern (Crown wax, Bego, Germany) for fabrication of definitive metal crown for 17. The wax pattern was placed on the cast and denture was seated on to it [Figure 4]a. After ensuring the proper adaptation of wax pattern of crown to the rest seat and clasps of CPD, it was invested and cast, followed by finishing and polishing of the crown [Figure 4]b. The full metal crown was placed on the abutment tooth to check for fit with the existing CPD intraorally [Figure 5]. Necessary occlusal adjustments were performed followed by polishing of the restoration and final cementation using glass ionomer luting cement (GC Fuji I, GC Europe N. V). On the follow-up visit, the patient was satisfied with the functioning of the crown and previous denture.
|Figure 1: (a) Maxillary arch with custom post and core in 17, (b) Mandibular arch|
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|Figure 2: Intraoral mirror image with cast partial denture seated to check adequate axial clearance from clasp for metal ceramic crown|
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|Figure 3: (a) Intraoral mirror image with acrylic resin provisional crown adapted to cast partial denture, (b) Putty index of provisional crown for wax pattern|
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|Figure 4: (a) Wax pattern with cast partial denture seated on the cast, (b) Metal crown with cast partial denture seated on the cast|
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|Figure 5: Intraoral mirror image of cast metal crown with cast partial denture seated in maxillary arch|
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| Discussion|| |
Literature describes various techniques [Table 1],,,,,,,,,,,,,,,, for retrofitting of a crown to existing CPD. The direct technique involves extended chairside time while forming the wax pattern for a crown directly in the patient's mouth without requiring working cast or CPD analog. The potential discrepancies that may occur during indirect procedures are avoided, but at the same time, the technique is limited to all metal crowns. Expertise and availability of laboratory personal cannot be utilized. Indirect techniques enable the formation of pattern for full metal crown or coping for ceramometal crown in the laboratory utilizing a working cast and either the actual partial denture or clasp replica/analog to contour the pattern.,,, Either the CPD has to be retained, or extensive procedure for analog formation is required, and also risk of potential errors during indirect procedures is there.
The direct-indirect technique involves the formation of pattern initially on die and then relined/corrected in the mouth at an additional intermediate appointment, before casting. This technique allows a ceramic coverage, but areas contacting clasp were retained in metal. The present technique is a direct/indirect technique where a provisional restoration formed on working cast.
The above-presented procedure describes a simple technique for fabrication of a new metal crown with axial contours and occlusal rest seat accurately fitting to an existing CPD. Adjustments for clasp assembly were performed on the provisional crown, whose index was used to fabricate definitive full contoured metal crown. The crown was checked on cast with existing CPD of the patient in occlusion before fitting it intraorally thus minimizing the chairside time for adjustments. Patient's CPD is required to be kept for 1 day to reduce chairside time, but if the patient does not want to leave his denture, then provisional restoration can be fabricated and contoured to fit the CPD using direct technique and its putty index for making wax pattern can be taken before cementation.
If the abutment is in esthetic zone and porcelain fused to metal crown is required then full contoured wax pattern can be cut back, except from rest seat area, for application of ceramic, using putty index to check axial contouring.
| Conclusion|| |
Simple technique described above can be recommended for retrofitting of new crown for an abutment to an existing CPD without requiring keeping denture in the laboratory for extended time. Since a blueprint of required final contours and rest seat is formed, chances of error are virtually eliminated, and minimal chairside adjustment is required.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]