Background:Masticatory forces cause fatigue to the dental luting agents, adversely affecting the retention of these cement-retained crowns. Sandblasting (SB) and diamond abrading the abutment surface improves the bond strength of luting agents. However, the effect of acid etching (AE) on the implant abutment surface and the effect of other surface modifications under masticatory load are yet to be documented.Purpose:The aim of the study was to evaluate the effect of abutment surface modifications on the retention of cement-retained restorations subjected to cyclic fatigue loads.Materials and Methods:Forty Ni-Cr copings were made on Cp-titanium laboratory analogs. The specimens were divided into two groups as Group I: Uniaxial tensile loading (UTL) and Group II: Offaxial cyclic loading followed by uniaxial tensile loading [CTL]. Further subgrouped as, subgroup I: Control (C), subgroup II: SB, subgroup III: AE, and subgroup IV: SB + AE. The copings were luted with Zn2(PO4)3 and subjected to uniaxial tensile loading. Copings were recemented, and CTL was conducted. Two-way analysis of variance was used as the statistical test of significance.Results:In relation to the subgroups, the bond strength of Zn2(PO4)3 was higher in Group I than in Group II. The bond strength in subgroup IV was superior in both Group I and Group II (547.170 N ± 5.752 and 531.975 N ± 6.221 respectively).Conclusions:For both UTL and CTL, abutment SB + AE elicited maximum coping retention followed by AE. Off-axial cyclic loading adversely affected the retention irrespective of the surface modifications.

Pre-prosthetic surgery is that part of oral and maxillofacial surgery which restores oral function and facial form. This is concerned with surgical modification of the alveolar process and its surrounding structures to enable the fabrication of a well-fitting, comfortable, and esthetic dental prosthesis. The ultimate goal of pre-prosthetic surgery is to prepare a mouth to receive a dental prosthesis by redesigning and smoothening bony edges.

Photoplethysmography (PPG) is an optical technique which measures blood volume changes in the arterial blood using red and IR LEDs of wavelengths 660[Formula: see text]nm and 940[Formula: see text]nm, respectively. This paper proposes a methodology to measure the pulse rate from the video signal obtained using an LETV-LE MAX 2 mobile phone’s camera and also to evaluate hypertension. The Android smartphone records the intensity of light reflected from the index finger. The recorded video is separated into red, green and blue frames. Since the red video frames returned useful plethysmographic information, they are filtered using Butterworth band-pass filter and power spectral density analysis was performed on them. The immediate peak gives the pulse rate of the respective subject. Fifteen features of pulse waveform are extracted and by performing the feature selection process, seven features are selected and they undergo classification process using a neural network. The feature selection process is performed by using the eigenvalues of the principal component analysis method. The eigenvalues obtained from this method show the degree of variation present in the data. The eigenvalue that is near or close to zero gives the principal components. The features that are selected by the feature selection process of principal component analysis method are peak interval, settling time, rise time, normalized PPG, peak-to-peak amplitude, first derivative and second derivative. While performing the classification process using a neural network, the accuracy of prediction was calculated for both the normal and hypertensive subjects.

Alveolar ridge atrophy poses a clinical challenge toward the fabrication of successful prosthesis. Resorption of mandibular denture bearing areas results in unstable non-retentive dentures associated with pain and discomfort. This article describes rehabilitation procedure of a patient with resorbed ridge with maximal areas of coverage to improve support and neutral zone arrangement of teeth to improve stability of denture.

Background: Polymerization shrinkage and fracture are the two common trouble shoots with denture base resins. Polymerization shrinkage affects the dimensional accuracy and fit of the prosthesis. The effect of zirconia (ZrO 2 ) nanoparticles on polymerization shrinkage is not documented yet. Purpose: The aim and objective of this study were to evaluate the impact strength and dimensional accuracy of heat-cured poly methyl methacrylate (PMMA) on reinforcement with ZrO 2 nanoparticles. Materials and Methods: Conventional heat-cure denture base resin (control) and the polymer reinforced with 3, 5, and 7 wt% of ZrO 2 nanoparticles were prepared and used in this study. Forty bar-shaped specimens were prepared and tested for impact strength using Charpy’s type impact tester. Forty denture bases were fabricated and checked for dimensional accuracy by measuring the distance between the denture base and the cast in two different sections using the travelling microscope. Results: The impact strength decreased with increased concentration of ZrO 2 and found to be least at 7 wt% concentration (2.01 ± 0.26 J/mm 2 ). The distance between the denture base and the cast significantly decreased both in the posterior palatal seal region (0.060 ± 0.007 cm) and mid-palatine section region (0.057 ± 0.006 cm) with ZrO 2 nanoparticles reinforcement and was found to be least at 7 wt% concentration. Conclusion: Reinforcement of heat-cured PMMA with ZrO 2 nanoparticles significantly increased the dimensional accuracy and decreased the impact strength.