Research Article
Volume 19 Issue 3 - 2020
Influence of Sandwich, Snowplow and Injection Molding Modified Composite Lining Strategies on the Microleakage of Class ii Proximal Box Cavities
Raji Viola Solomon1*, P Karunakar2, P Shanti Priya3, Md Abdul Wahed3 and Hima Ranjana P4
1Professor, Department of Conservative Dentistry and Endodontics, Panineeya Institute of Dental Sciences and Research Centre, Hyderabad, Telangana, India
2Professor and Head of Department, Department of Conservative Dentistry and Endodontics, Panineeya Institute of Dental Sciences and Research Centre, Hyderabad, Telangana, India
3Senior Lecturer, Department of Conservative Dentistry and Endodontics, Panineeya Institute of Dental Sciences and Research Centre, Hyderabad, Telangana, India
4Dental Surgeon, Department of Conservative Dentistry and Endodontics, Panineeya Institute of Dental Sciences and Research Centre, Hyderabad, Telangana, India
*Corresponding Author: Raji Viola Solomon, Professor, Department of Conservative Dentistry and Endodontics, Panineeya Institute of Dental Sciences and Research Centre, Hyderabad, Telangana, India.
Received: January 09, 2020; Published: February 28, 2020


Background and Aim: Packable or condensable composites are primarily indicated as a posterior restorative material due to their improved mechanical properties such as decreased wear, increased packability and depth of cure. However they have certain limitations like polymerization shrinkage and microleakage at cemento-dentinal margins. To address aforesaid shortcomings, placement of an intermediate liner below composite restorative layer has been suggested. The aim of the present study was to investigate the microleakage at the proximal box of class II preparation restored with posterior packable composite resins, different liners and lining techniques as a measure to decrease polymerization shrinkage. 

Materials and Methods: Thirty seven freshly extracted, intact, non-carious human mandibular molars were selected.  Standardized Class II box preparation were made with cervical margin 1 mm above the cemento-enamel junction on both proximal surfaces of each tooth. 

The samples were randomly divided into five groups based on the restorative protocol. Group I (n = 5): No liner applied and restored incrementally with packable composite, Group II (n = 8): Open sandwich technique using flowable composite which was precured followed by incremental build-up of packable composite resin,  Group III (n = 8): Snow plow technique where flowable composite liner and adhesive were co-cured together followed by incremental packable composite build-up, Group IV (n = 8): Injection molding technique where flowable composite liner, adhesive and the initial increment of composite co-cured simultaneously followed by packable composite build up, Group V (n = 8):  Resin modified glass ionomer cement (RMGIC) placed as a liner of 1mm thickness which was precured followed by incremental build-up of packable composite resin. 

The restorations were then thermocycled for 1500 cycles with temperature range of 50C to 600C +50C with a dwell time of 20 seconds for each temperature.   Using modeling wax the root apices of the teeth were sealed. The surface of all the teeth were coated using 2 layers of nail varnish leaving 1mm window around cavity margin of restoration. Then the teeth were submerged in 2% methylene blue solution for 24 hours at 37oC. Later the specimens were sectioned and evaluated under stereomicroscope. The obtained data was analyzed through    Kruskal-Wallis ANOVA with post-hoc Conover test.

Results: There was overall significant difference in terms of microleakage among the five groups (< 0.05). Post-hoc Conover test showed that injection molding technique (Group IV) had significantly lowest mean score (0.78) than other four groups indicating that the microleakage of packable composite significantly reduced by co- curing liner, adhesive, and composite layer together. Similarly, open sandwich technique with Flowable composite liner (Groups II) with a mean score of 1.56 and Snow plow technique (Group III) with a mean score of 1.41 showed significantly less microleakage compared to control group with a mean score of 2.30. This clearly suggests that flowable composite liner reduced the microleakage but open sandwich technique with RMGIC (Group V) could not show satisfactory results with a mean score of 1.75 which is close to control group though statistically insignificant.

Conclusion: According to the results of the present study, injection molding technique performed better with least microleakage. Use of liner under packable composite improved the sealing ability in class II box preparation compared to conventional method.

Keywords:Polymerization Shrinkage; Microleakage; Snow Plow Technique; Injection Molding Technique; Composite Resin Restoration; Packable Composite


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Citation: Raji Viola Solomon., et al. “Influence of Sandwich, Snowplow and Injection Molding Modified Composite Lining Strategies on the Microleakage of Class ii Proximal Box Cavities”. EC Dental Science 19.3 (2020): 01-09.

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