This in vitro study evaluated and compared the abrasion resistance of types IV and V gypsums, resin-modified type IV and type V gypsums, synthetic gypsum, and epoxy resin die material at two different time intervals spanning a period of 24 hours.

A total of 10 dies of each die material were fabricated and tested for abrasion resistance at each time interval. An average of five readings was taken for the test, measuring the rate of abrasion of the materials.

All the tested properties of the epoxy resin material were far superior to those of the other materials (being tested). Resin-modified type IV gypsum had significantly better abrasion resistance than its type V counterpart at setting. However, when tested at 24 hours, both materials had comparable resistance to abrasion, which was the highest among the gypsum-based materials.

Epoxy die resin had the most superior physical properties of all. A significant decrease in the rate of abrasion (-38 to -83%) was noted, when the gypsumbased products were tested at 24 hours. From the data obtained in this study, it is recommended that when gypsum-based materials are used, to wait at least 24 hours prior to separating casts from impressions (and subsequent laboratory procedures) to avoid damage to the casts and dies.

RR IV: Resin modified type IV gypsum; RR V: Resin modified type V gypsum; S: Synthetic gypsum; V: Type V gypsum; IV: Type IV gypsum.

Wankhade SV, Sanghavi KV, Rajguru V, Lokade J. A Comparative Evaluation of Six Commonly used Types of Die Materials for the Property of Abrasion Resistance, at Two Time Intervals: An in vitro Study. Int J Prosthodont Restor Dent 2013;3(1):1-6.

To compare the proximal contacts and contours in class II composite restorations in premolars achieved with Automatrix band with separation ring vs Automatrix band alone.

A total of 188 premolar teeth with proximal cavity were assigned on alternate basis in two groups. Intervention group teeth received Automatrix band with separation ring using clamp forceps, while the control group received Automatrix band alone. All preparations were restored with P-60 composite (3M-ESPE Dental, USA). The outcome (proximal tightness) was determined by a blinded assessor. Chi-square test was applied to compare the contact tightness between the two groups. Spearman's rank correlation coefficient was applied to determine any correlation between the contact tightness with proximal contours. p-value of 0.05 was taken as significant.

The intervention group exhibited better proximal contacts than the control group (p-value 0.040). There was no correlation between the contact tightness and the proximal contours.

The use of separation ring along with Automatrix matrix band in class II composite restorations resulted in significantly better proximal contacts than Automatrix band alone. However, the separation ring does not contribute in producing an additional improvement in the proximal contours. The proximal contour has no relationship with the proximal contact tightness.

Several techniques have been advocated to get tight contacts in composites including interdental separation ring. Our study focuses on using separation ring with circumferential matrix band instead of a sectional band. Moreover, we have attempted to study proximal tightness and proximal contours of composite restoration as separate variables.

Khan FR, Umer F, Rahman M. Comparison of Proximal Contact and Contours of Premolars restored with Composite Restoration using Circumferential Matrix Band with and without Separation Ring: A Randomized Clinical Trial. Int J Prosthodont Restor Dent 2013;3(1):7-13.

This study is undertaken to evaluate the dependence of bond strength of 100% fresh nonprecious alloy and the combination of 50% recast (used) alloy and 50% fresh alloy with three different veneering ceramic material.

To evaluate the shear bond strength between new and recast alloy nonprecious Ni-Cr alloy (System KN®, Adentatec, Germany) was used with three different commercially available ceramics. A total of 60 samples were prepared and divided in two groups depending on the new or recast alloy. The 30 specimens of new alloy (group A) and 30 specimens of recast alloy (group B) were fabricated. Each group was again divided into three subgroups of 10 specimens for ceramic veneering Vita VMK-95 [V], IPS Classic [I] and Noritake [N] as veneering ceramic materials. Thus, six subgroups were formed as groups AV, AI, AN, BV, BI and BN. Groups AV and BV were veneered with Vita Ceramics, Groups AI and BI were veneered with IPS Classic (Ivoclar) and Groups AN and BN were veneered with Noritake. Then, shear bond strength between new and recast alloy was analyzed for each type of ceramics using MTS machine.

The bond strength between new [group A] and recast alloy [group B] using three different veneering ceramics were evaluated. It was found that the new or the fresh alloy had highest shear bond strength than the recast alloy. Statistically, it was found that there was significant difference in bond strength between the new and recast alloys, when same type of ceramics was compared. When comparing ceramics, the Noritake group had highest bond strength, while other groups, that is, Vita and Ivoclar had comparatively low bond strength.

From this study, conclusion can be drawn that the use of 50% recast alloy shows reduction in bond strength values. Therefore, the use of recast alloy should not exceed more than 50%, as it would compromise the properties of alloy and the efficacy of bond strength between ceramic and alloy.

Gosavi S, Wadkar A, Gosavi SY. Ceramometal Bond Strength Analysis using New and Recast Nonprecious Alloys with Three Different Ceramics. Int J Prosthodont Restor Dent 2013;3(1):14-20.

The retention of complete dentures is frequently difficult in edentulous patients with a severely resorbed residual alveolar ridge. In such cases, implant overdentures having a stronger retention force are useful. Although there are various types of attachment systems for implant overdentures, they are frequently complicated. We are, therefore, developing a simple attachment system focusing on a soft lining material for the female connector. The purpose of this study was to evaluate the retention force of implant overdentures applying a soft lining material for the attachment.

The models in which seven male and female connector pairs were used. As the control, a rubber O-ring attachment system, in which a rubber O-ring female was paired with a metal ball anchor (male), having a diameter of 1.7 or 2.2 mm. In the attachment system with a soft lining material, a female component was made up of soft lining material paired with a male having a diameter of 1.7, 2.2, 2.5, 2.7 or 3.0 mm. In measuring the retention force, the maximum force required to dislodge the male from the female was recorded by a digital force gauge.

With the rubber O-ring, the retention force was 2.9 ± 0.2 N for the 1.7 mm male and 3.3 ± 0.3 N for the 2.2 mm male; these values were higher than the respective retention forces when using a soft lining material as the female and a male of the same diameter. However, with the female comprising soft lining material, the retention force exceeded 4 N for the 2.5, 2.7 and 3.0 mm males and was higher than the retention forces for the rubber O-ring.

The proposed attachment system with soft lining material for implant overdentures provides a clinically sufficient retention force when the diameter of the male exceeds 2.5 mm.

Koike T, Ueda T, Noda S, Ogami K, Patil PG, Sakurai K. Development of New Attachment System with Soft Lining Material for Implant-retained Complete Denture. Int J Prosthodont Restor Dent 2013;3(1):21-24.

Debnath N, Gupta R, Meenakshi A, Ramkumar K, John J. A Simplified Approach to Fabricate a Custom-made Ocular Prosthesis. Int J Prosthodont Restor Dent 2013;3(1):25-29.

Kumar S, Singh DB. Hoarseness of Voice: Presentation of Neglected Denture Esophagus. Int J Prosthodont Restor Dent 2013;3(1):30-32.

Bansode PV, Pathak SD, Deore RB. Management of a Complicated Crown-Root Fracture using Single-Visit Endodontic Treatment and Fiber Post as an Intracanal Anchorage. Int J Prosthodont Restor Dent 2013; 3(1):33-36.

Debnath N, Gupta R, Devi AS, Meenakshi A, Ramkumar K. Prosthodontic Rehabilitation of an Ectodermal Dysplasia Patient with Artificial Saliva Reservoir in Complete Denture. Int J Prosthodont Restor Dent 2013;3(1): 37-41.