Yashwani jain, Santosh Kumar Singh, Pankaj Mishra, Shubhashree Rajput, Sakshi agrawal, Kapil Malviya

ABSTRACT

Background: Polymerization shrinkage in resin-based composites can lead to compromise of the tooth–restoration interface, particularly in Class II cavities where gingival margins are often located in dentin. Modifications in restorative technique aim to enhance marginal adaptation, reduce microleakage & minimise interfacial gap without necessarily altering the restorative material. Aim: To comparatively evaluate microleakage in Class II composite restorations using progressive restorative techniques. Materials and Methods: 48 extracted human premolars were selected and standardized Class II (mesio-occlusal/distal-occlusal) cavities were prepared with gingival margins positioned 1 mm below the cementoenamel junction. The samples were randomly allocated into four groups (n = 12): Group I – conventional incremental technique (control), Group II – snowplow technique, Group III – stress-reduced direct composite (SRDC) technique, and Group IV – SRDC with polyethylene fibre interposition. A uniform adhesive protocol and the same composite restorative material were used for all specimens. After restoration, samples were stored in distilled water for 24 hours and subjected to thermocycling between 5°C and 55°C. The teeth were then coated with nail varnish except for a 1 mm window around the restoration margins and immersed in 2% methylene blue dye for 24 hours. Specimens were sectioned bucco-lingually through the proximal box and evaluated under a stereomicroscope at 4x magnification. Microleakage was assessed using a 0–3 scoring system based on the extent of dye penetration from the gingival margin toward the axial wall. Data were analyzed using parametric statistical tests with significance set at p < 0.05. Results: The Conventional Incremental Technique demonstrated the highest degree of dye penetration indicating the poorest marginal seal. The Snowplow Technique exhibited moderate dye penetration, suggesting improved adaptation compared with the conventional technique. The SRDC Technique showed only superficial dye penetration , reflecting better marginal integrity. The SRDC with Polyethylene Fibre Technique demonstrated the least microleakage, indicating superior marginal adaptation and sealing ability. Conclusion: The results suggest that the incorporation of stress-reduction strategies significantly improves marginal sealing in Class II composite restorations. Furthermore, the addition of polyethylene fibre reinforcement to the SRDC protocol appears to offer the greatest resistance to microleakage, indicating its potential value as an adjunctive restorative approach for improving restoration longevity.