Indru Punwani

Glass ionomer microleakage from preparations by an Er/YAG laser or a high-speed handpiece

OBJECTIVE The purpose of this study was to compare microleakage of glass ionomer materials (GIC) using two different modes of cavity preparation: a high-speed hand piece and an erbium/yttrium-aluminum-garnet (Er/YAG) laser. METHODS Eighty caries free permanent molar teeth had class V preparations cut on both the buccal and lingual surfaces. The high-speed hand piece was used to prepare a class V cavity preparation on the buccal surface and an Er/YAG laser was used to prepare a class V cavity preparation on the lingual surface. GIC or resin modified GIC was used as the restorative material. The teeth were thermocycled for 7000 cycles, placed in 2% basic fushin for 24h, sectioned in the center of each restoration, and analyzed under a stereomicroscope. RESULTS There was no statistical difference in microleakage between the two modes of cavity preparations. The gingival margins had more microleakage than the occlusal margins for both GIC materials and the resin modified GIC showed significantly more leakage than the conventional GIC. CONCLUSIONS The Er/YAG laser provided an equivalent method of tooth removal when evaluated for microleakage of GIC materials compared to a high-speed hand piece.

Sealant bond strengths of CO2 laser-etched versus acid-etched bovine enamel

The purpose of this study was to evaluate sealant shear bond strength on bovine enamel with standard acid etching compared with CO2 laser etching.

Use of a palatal stabilizing device in prevention of palatal grooves in premature infants

A prospective, randomized study using an acrylic palatal stabilizing device (PSD) was conducted to evaluate the effectiveness of this device in preventing disruptions in palatal architecture. A total of 26 premature infants with birth weights of 540 to 1740 g, and intubated orally for a period varying from 7 to 109 days were randomized to control and experimental groups. All neonates in the control group developed palatal grooving ranging from 2 to 5 mm in depth, whereas those in the experimental group (with a PSD) showed no evidence of palatal grooving. We conclude that a PSD is an effective preventive device in premature orally intubated infants.

Degree of polymerization between adjacent visible light-cured composite areas

Abstract The degree of polymerization between 2 adjacent visible light-cured composite areas was characterized by hardness measurements and scanning electron microscopy. It was observed that minimum of 20 s exposure for 1 mm overlap and 40 s for 0.5 mm overlap, between 2 light-exposed areas, produced optimal hardness. The interface between the areas was uniformly cured. The 1 mm overlap would produce a homogeneous structure, optimal hardness and eliminate any possibility of partially cured area in the filling.

Use of the Pala-nate device in the prevention of palatal grooves in premature, intubated infants.

Objective Previous studies demonstrated that the use of a custom-made intraoral acrylic appliance, known as a palatal stabilizing device, prevents palatal groove formation and reduces the frequency rate of accidental extubations in premature, intubated babies. In this study, we compared the effectiveness of a prefabricated palatal device with an acrylic custom-made palatal stabilizing device. Specifically, we compared the stability, fit, and retention of these two devices. Design Randomized comparative study. Setting Clincal trial. Patients A total of 70 medically stable, premature, intubated babies. Interventions A total of 70 medically stable, premature, intubated babies randomly received Pala-nate (experimental group, n = 34) or palatal stabilizing device (control group, n = 36). Measurements and Main Results Differences among birth weight, gestational age, and period of intubation of the two groups were statistically nonsignificant at p ≤ .05. Although both appliances were effective in the prevention of palatal grooves, the Pala-nate was less retentive, thus requiring greater monitoring, and it was associated with a larger number of accidental extubations. The differences between the two groups were statistically significant at p ≤ .05. Conclusions We concluded that the custom-made, acrylic, palatal stabilizing device was more stable and more effective in the prevention of spontaneous extubations in premature orally intubated infants.

Interface corrosion in amalgam-to-amalgam and amalgam-to-nonprecious metal crown couplings.

This study examined the contact surface area in the coupling of a class II amalgam restoration with another class II amalgam restoration or with a stainless steel or nickel-chrome crown in 1% NaCl solution. The characterization of interfaces was carried out by using SEM and EDX microanalysis. The results indicate that the coupling of an amalgam-stainless steel crown and an amalgam-inconel crown in NaCl solution forms a deposit on the crown surfaces. This deposit contains all the constituents of corrodible phases of amalgam, including Zn. If amalgam restorations in adjoining teeth are contemplated, non-Zn-containing amalgam alloys of the same composition should be considered.