THE USE OF INLAY PATTERN RESIN AS AN ABUTMENT CROWN TEMPLATE FOR REMOVABLE PARTIAL DENTURES: CLINICAL REPORT:

Patients with removable partial denture need abutment tooth as retainer for the clasp. In some cases, this tooth requires endodontic treatment or even jacket crown so it can be used as a clasp retainer. For patient with removable partial denture, post core and crown fabrication in abutment teeth require adjustments to the crown to fit with denture clasp.  First case, a 23-year-old male patient with fractured lower second premolar tooth because of previous metal restoration failure and had been treated with root canal treatment. The tooth was used as an abutment for removable partial denture that was still in good condition. The tooth was later treated with cast post and core with PFM (Porcelain fused to metal) crown. Second case, a 60-year-old female patient came to the clinic with a complaint of fracture in upper first premolar. This tooth was also used as abutment for maxillary framework partial denture. A template made of pattern resin was made to reproduce the dentures for both cases. Acrylic resin has good accuracy and stability to reproduce parts of the denture. The advantage of this technique is that patients can use their denture during fabrication of the crown.


INTRODUCTION
Crowns or other restorations fabricated in order to repair damaged abutment tooth to adjust to an existing removable partial denture is considered a complicated procedure. 1 Patients often refuse to fabricate new removable partial denture (RPD) or had it taken out during treatment when the abut-ments were damaged while the RPD was still usable.
There are several types of plastics which are also known as polymers used in prosthetic dentistry, including acrylic and rubber-reinforced acrylic polymers. Out of all plastic polymers used in the field of prosthetics, acrylic comprises 95%. 2 Die fabrication technique for fixed or removable denture can be simple, accurate and reliable 1,3 . Resin copings made from inlay resin pattern are used to record the space between the teeth and RPD clasp, assist in occlusal registration, verify the dimensional accuracy of the dies and visualize the marginal adaptation of the retainers. 3 An existing method to fabricate abutment teeth of previously existed RPD is by using inlay resin pattern to duplicate RPD clasp assembly which will later be transferred to working cast. The replica will merge with the working cast as a removable component and assists in contouring the crown. 4

CLINICAL REPORT
A 23-year-old male patient with difficulty in eating as a result of fractured mandibular left second premolar because of previous metal restoration (amalgam) failure which had been treated with root canal treatment came to Maranatha Dental Hospital for consultation regarding available treatment options. A clinical examination revealed that the mandibular left second premolar was used as the abutment for his acrylic removable partial denture, which was still in good condition. He was using removable partial denture (RPD) to replace the missing mandibular right and left molars. Discussion result showed that the patient wanted a strong restoration to replace his fractured tooth and declined a new RPD. Post and core crown were planned to replace the fractured tooth.
Diagnostic cast revealed a short tooth (mandibular left second premolar height was 2 mm). The tooth was prepared to remove the remaining dentin (  The gutta percha was removed, then an impression of the root canal was made with PVS and sent to laboratory for post fabrication. The post was tried in and inserted (Fig. 2), Then, an acrylic template resin was made (Fig. 4) after bite registration using PVS with the RPD in the patient (Fig. 3).  A 60-year-old female patient presented to Department of Prosthodontic, Padjadjaran University Den-tal Hospital with fractured of left maxillary second premolar filling (Fig. 6). She reported difficulty in masticating. The tooth was also used as an abutment for maxillary framework partial denture. The patient refused to lend her RPD during treatment. Full crown was indicated because the fracture was large.
After preparation for the full crown is finished, the working model was made. Acrylic resin template (Duralay) was made in the prepared tooth die (Fig.  7) as the abutment for polyether bite registration material (Ramitec, 3M). The acrylic resin template was tried in (Fig. 8). Bite registration was made to duplicate clasp contour (Fig. 9). Used the same acrylic resin template (Duralay) to duplicate the clasp (Fig. 10). The crown was made with the resin template used as a guide (Fig. 11). Crown was tried in the mouth (Fig. 12) and was inserted after glazing (Fig. 13).

DISCUSSION
Acrylic polymers has been widely used in prosthetic dentistry as denture base, artificial teeth, denture repair material, impression tray, provisional restoration, and maxillofacial prosthetics. 5 Inlay pattern resin (Duralay) usage ensures no breakage, chipping, distortion or temperature changes during trimming, handling, and investing due to its dense, accurate, and non-shrinking pattern. 6 The cast should be attached to the same maxillary mandibular pretreatment relationship if the goal of restorative treatment is to maintain patient intercuspation and preexisting occlusal dimensions after crown preparation. In order to accurately mount working and opposing cast, acrylic resin transfer copings on top of prepared teeth is used to record the relationship. 7 Post core crown, full crown or other restoration methods can be used as prosthetic treatment for RPD abutment or fixed denture. There are 3 techniques in fabricating crown fitting the partial denture, i.e. direct, indirect, and combination. Acrylic resin and inlay wax are often used in direct technique in mouth to make a custom pattern which can reproduce the contour of clasps. Indirect technique uses pick-up impression to produce crown pattern from wax adjusted to denture framework. Combination techniques is a combination of both direct and indirect technique. 8 Preliminary resin pattern was made directly to the teeth and contouring was done using wax on the working cast in direct-indirect technique. A crown pattern on a die was made and adjusted inside the mouth or on the die after previously tried in the mouth. 8 Addition silicone and polyether have been used as occlusal registration materials. Both materials have short working time and longer time inside mouth compared to other elastomer impression materials. These materials also have high stiffness and low strain during compression, lower flow and no dimensional changes. 5 Both cases in this report uses addition silicone and polyether, in which the first case used the former and the second case used the latter. The difference between addition silicone and polyether is that the former has low dimensional changes after removal. 5

CONCLUSION
The use of inlay pattern resin as coping and duplication of the clasps of removable partial denture is a simple and accurate technique. A replica of the clasp assembly can be generated and transferred to a traditional working cast as a guideline for crown fabrication, therefore the RPD can still be used by the patient during treatment.