Soft denture liners act as a cushion for the denture bearing mucosa through even distribution of functional load, avoiding local stress concentrations and improving retention of dentures there by providing comfort to the patient. The objective of the present study was to compare and evaluate the tensile bond strengths of silicone-based soft lining materials (Ufi Gel P and GC Reline soft) with different surface pre treatments of heat cure PMMA denture base acrylic resin. Stainless steel dies measuring 40 mm in length; 10 mm in width and 10 mm in height (40 × 10 × 10) were machined to prepare standardized for the polymethyl methacrylate resin blocks. Stainless steel dies (spacer for resilient liner) measuring 3 mm thick; 10 mm long and 10 mm wide were prepared as spacers to ensure uniformity of the soft liner being tested. Two types of Addition silicone-based soft lining materials (room temperature polymerised soft lining materials (RTPSLM): Ufi Gel P and GC Reline soft) were selected. Ufi Gel P (VOCO, Germany), GC Reline soft (GC America) are resilient, chairside vinyl polysiloxane denture reliners of two different manufacturers. A total of 80 test samples were prepared of which 40 specimens were prepared for Group A (Ufi Gel P) and 40 specimens for Group B (GC Reline soft). In these groups, based on Pre-treatment of acrylic resin specimens each group was subdivided into four sub groups of 10 samples each. Sub-group I-without any surface treatment. Sub-group II-sand blasted Sub-group III-treated with Methyl Methacrylate monomer Sub-group IV-treated with chemical etchant Acetone. The results were statistically analysed by Kruscal Wallis test, Mann-Whitney U test, and Independent t test. The specimens treated with MMA monomer wetting showed superior and significant bond strength than those obtained by other surface treatments. The samples belonging to subgroups of GC Reline soft exhibit superior tensile bond strength than subgroups of Ufi Gel P. The modes of failure of all specimens were mostly adhesive in nature. Surface pre treatments by chemical means improved the bond strength between the silicone liners and denture base.

Aim: The aim of this systematic review was to investigate the marginal adaptation of three or four unit fixed dental prosthesis (FDP) fabricated with digital impression techniques to those fabricated using any other impression technique. Settings and Design: Database/electronic searches were conducted till August 2019 in PUBMED-MEDLINE, SCOPUS, and Cochrane library. To identify published articles, multiple keywords were used to develop a search strategy in various combinations. Manual searching of articles was also done. Clinicaltrials.gov.in WHOICTRP and CTRI websites were also searched. Two independent reviewers (TP and VK) assessed eligibility for inclusion, extracted data, and assessed quality using the Cochrane risk of bias tool. Results: Database search identified 497 citations and four citations through manual search. After removing duplicates and going through abstracts, 23 articles were perused for full-text screening. Two articles met the inclusion criteria; characteristics were described qualitatively, with two studies having overall low risk of bias. Conclusions: Marginal adaptation of FDPs fabricated using the digital and conventional impressions method was within the clinically acceptable limits. However, more robust clinical trials need to be conducted with large sample size to validate the conclusions.

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