Semi-Direct Composite Restorations- A Clinical Report

MALAYSIAN DENTAL JOURNAL Semi-Direct Composite Restorations- A Clinical Report Berhanuddin Muhamad Asyraf, Tong Wah Lim Faculty of Dentistry, University Teknologi MARA, Malaysia ABSTRACT In nowadays world, aesthetic dentistry has becoming a trend with the improvement of dental technology and materials. Composite resin becomes the material of choice as it offers good aesthetics, longevity and allow for minimally intervention approach. There are various ways of composite restorative techniques recommended to make out the best restorative outcome. Direct restorative technique promise acceptable cost, appointment time and color matching but it is a challenge for the clinician especially for extensive cavities. Indirect technique is good for extended cavity and providing less operator error, however, it requires multiple appointments, higher cost and laboratory involvement. Computer-aided design/ computer-aided manufacturing (CAD/CAM) technology might reduce the number of appointments, however, it will cause more financial burden to the patient and the clinician. Therefore, semi-direct technique was introduced, it combines the benefits of direct and indirect technique and this technique can be done without the use of any advanced technology and give out a good treatment outcome. Key Words: semi-direct technique, composite restorative technique, composite resin

Introduction Minimally intervention aesthetic dentistry has now becoming a trend, as people are more aware about aesthetic dental work and preservation of tooth structure. Composite resin is the most popular adhesive restorative material that allows clinician to produce an economic and long lasting aesthetic restorations. 1 However, failure of composite restorations was still well reported and documented in the literature. Paolo et al. reported higher probability of failure in molars and large restorations for composite restoration that was caused by poor moisture control and more complex tooth restorative procedure. 2 Wilson et al. revealed that tooth-material bonding strength was deteriorated by moisture, polymerization shrinkage, and clinical wear that subsequently lead to failure of a restoration. 3 Polymerization shrinkage might be minimized but not totally eliminated by manipulating the techniques of restoring the cavity. 4 There are various ways of composite restorative techniques recommended to restore a posterior cavity including direct, semi-direct and indirect techniques. Dietschi et al. claimed that these three techniques have been widely practiced according to number, extension and location of a restoration. 5 Direct restorative technique promise acceptable cost, appointment time and color matching but it is a challenge for the clinician especially for extensive cavities. Indirect technique is good for extended cavity and providing less operator error, however, it requires multiple appointments, higher cost and laboratory involvement. 6 Extensive posterior cavity is best indicated for indirect technique as it offers good control of occlusal and interproximal anatomy, however, there was no significant difference reported if we use it for a medium size posterior cavity. 7

Computer-aided design/ computer-aided manufacturing (CAD/CAM) technology might reduce the number of appointments, 7 however, it will cause more financial burden to the patient and the clinician. Van Meerbeek et al. also revealed that CAD/CAM porcelain and composite inlays which were luted with dual cured luting composite showed the best marginal adaptation. 8 Whereas, semi-direct technique can be done without the use of any advanced technology but still produce a good treatment outcome. With regards to the semi-direct technique, the composite resin build-up is made by the clinician either intraorally or extraorally, thus reducing the number of appointment and excluding the laboratory involvement. 4 Composite resin build up is done on isolated cavity intraorally, followed by finishing and polishing extraorally, and cementation is carried out at last. 9 Al-Harbi et al. reported that removing the restoration after composite resin hardening was a challenge for intraoral approach despite giving the most accurate marginal fitting for the restoration. 9,10 It is due to the micro retention created from rough surface of diamond bur and the cavity configuration itself. 4 Hence this limit the use of intraoral approach for occlusal, mesio-occlusal or disto-occlusal cavity where cavity configuration disable the removal of restoration. 9 Pertaining to extraoral approach, Spreafico recommended taking the impression of a cavity, and making the silicone working model out of it, followed by doing the restoration extraorally. The author was convinced that this will enable less divergent cavity preparation or being more conservative in removing the tooth structure. 4

Case Report A 30-year old male came with asymptomatic large defective occlusal amalgam restorations on tooth 46 and 47, which were indicated for replacement (Figure 1). A periapical radiograph was taken, and we found that the radiolucency has extended to the inner third of the dentin. Due to the size of the cavity and financial limitations for indirect restorations, semi-direct restorations was suggested as this patient s best treatment option. Pre-operative occlusal contact was checked using metallic Shimstock film (Bausch Arti- Fol) to ensure conformation of occlusion post-treatment. Shade selection was done using manufacturer shade guide (Ceram.x one Universal, Dentsply) in comparison with the adjacent tooth shade. Infra alveolar nerve block was administered for pain control, followed by a rubber dam placement to obtain optimal moisture control. Caries free was completed in a conservative manner, by limiting to the removal of infected dentin. Selective enamel etching was performed using 34% phosphoric acid and universal bonding agent (Prime & Bond One Select, Dentsply) applied prior to placement of the siqveland matrix band. Then, smart dentin replacement (SDR, Dentsply) was used to simultaneously restore the cavities and achieved an ideal cavity sealing. It was cured with a high power light-emitting diode (LED) curing light (SmartLite Focus, Dentsply) for 20 seconds. Onlay tooth preparation was carried out using course and fine diamond bur, as suggested by Dietschi D & Spreafico R. 11 Lastly, white stone finishing bur was used to smoothen the prepared surface and remove any unsupported enamel (Figure 2).

Heavy bodied washed impression with light bodied addition silicon material (Aquasil, Dentsply) was taken on the working side (Figure 3). The working silicon model was fabricated by giving a negative impression on the impression done earlier using the putty washed with thin light bodied silicon impression material. Thin petroleum jelly was used as a separating medium to enable easy separation of working model from the impression. Multi-layering composite build-up technique was performed on the silicon working model. A nanohybrid composite resin material (Ceram-x one, Dentsply) was used through several incremental layers of 1.5 to 2.0mm thickness. Each incremental layer was cured for 20 seconds, keeping the distance of light cure tip within the range of 2mm from the restoration. Universal shade was determined and directly shaped into ideal anatomy (Figure 4). Once the composite build-up was completed, the fitting and occlusion of the restoration was checked intraorally. The prepared tooth surfaces were pumiced and the fitting surfaces of the onlay were sandblasted using 50 micron alumina and steam cleaned to remove debris as well as to produce surface roughness for an improved bond strength. The surface of prepared tooth and was etched using 34% phosphoric acid, followed by rinsing with water spray for 20 seconds. The silane coupling agent was applied on the fitting surface of the onlay or 1 minute. The bonding agent was then applied on the prepared tooth surfaces and on the onlay fitting surfaces. Heated composite resin at 65 degrees in 2 minutes with selected shade was used as a luting agent (Figure 5). Digital

pressure was applied occlusally to seat the onlay into the cavity with jiggling motion followed by application of a scaler tip with cotton roll on the restoration. Dental probe and dental floss were used to remove the excessed luting composite, followed by the use of a micro brush. Curing was done for at least 20 seconds per surface. White stone finishing bur was used to finish the margins. Final polishing was done using a composite polishing bur (Enhance, PoGo, Dentsply). Lastly, tooth characterization on the fissures was carried out using intensive color resin (Color Plus, Kerr) to mimic the natural anatomy of the adjacent tooth (Figure 6). Discussion The amalgam restorations on tooth 46 and 47 were indicated for replacement due to secondary caries. 12 Mjör & Toffenetti reported that secondary caries mostly located more gingivally to the existing restoration. 13 Replacement of large size restorations using composite resin has raised some concerns including polymerization shrinkage stress that may cause poor marginal adaptation, leading to post-operative pain and recurrent carries. 14,15 Large restoration will result in increased stress in the tooth itself due to tooth s resistance to the polymerization shrinkage reduced with tooth structure lost. 16 Therefore, bulk-filling composite resin (SDR, Dentsply) was chosen to replace the lost dentin structure in this case to reduce the polymerization shrinkage, and to improve the tooth-restoration interface adaptation. 17

Preheated composite resin was selected as the luting cement in this case due to its improved adaptation to the tooth structures, allowing easier placement and handling, while achieving and improved durability and reduced risk of micro leakage. 16 This technique has been well reported in other studies. 19,20 The semi-direct technique, adopted in this case, acquires the advantages of both direct and indirect techniques. This technique eliminates lab involvement, while allowing clinicians a better control of the quality of the final prosthesis. 9 Van Dijken also concluded in his clinical study that semi-direct composite resin inlay/ onlay lasts longer, with an improved marginal adaptation and a low incidence of secondary caries. 21 Immediate cavity sealing with an adhesive resin composite layer, practiced in this case, provides some benefits. 19 It was found that resin composite layer improved the protection of sealed dentin against mechanical and thermal stimuli during provisional phase, thus avoiding dentin hypersensitivity. 19 It also acted as a physical barrier against mechanical surface treatment during cementation, keeping the integrity of the thin bonding layer. 22 Chemical stability may be improved by using the same restorative composite resin for cavity sealing and luting of the restoration, as it has been found to provide identical biomechanical properties between different layers of the restoration. 9 In addition, optimal dentinal adhesion may be achieved via immediate sealing, performed while the freshly cut dentin is still clear from any temporary cement contamination. 23 Layering of composite resin over the sealed dentin may also prevent cavity undercuts, - thus allowing minimal tooth preparation. 19

Conclusion Semi-direct technique, which combines the advantages of both direct and indirect restoration techniques, overcome the time and cost issues of indirect technique, without compromising the treatment outcome of the restoration. Acknowledgement This work was partly funded by RAGS grant 600-RMI/RAGS 5/3 (117/2013). Corresponding Author: Berhanuddin Muhamad Asyraf Faculty of Dentistry, Universiti Teknologi MARA, Sungai Buloh Campus, Jalan Hospital 47000 Sungai Buloh, Selangor, Malaysia. Telephone: 013-4080231 Fax: 03-55435803 Email: the4flater@yahoo.com

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Figure 1: Pre-operative view.

Figure 2: Immediate dentin sealing using bulk-filling composite resin. Figure 3: Chairside impression was taken.

Figure 4: Composite onlays were fabricated on silicon model. Figure 5: Heated composite resin was chosen as luting cement

Figure 6: Both onlays were cemented and tooth characterization on the fissures was performed.