Journal of Dental Sciences

1-8

Authors: Tatjana Puskar

Background: Reinforcement of PMMA has been an issue since it has been first introduced in the dental practice. Various improvements have been suggested, out of which addition of nano particles presents most recent method. Effect of nano particle addition on mechanical and biological properties off PMMA materials remains to be determined. Materials and methods: The materials used were mixed with SiO2 nano particles ranging from 0.05% to 2 wt.%. Determination of flexural strength and modulus of elasticity was done by three-point bending test on Universal testing machine. Most successful nano-modified materials were chosen for cytotoxicity assessment using L929 and MRC 5 cell lines. Results: The highest values for flexural strength and modulus of elasticity were obtained with 0.05% or 0.1% nanosilica addition, depending on the composition of the material. The secondary peek was observed at 2%. Addition of silica nano particles affected cytotoxicity of the material that was concentration depended. Conclusion: Modulus of elasticity and flexural strength are strongly dependent on material nano-particle content. All of the materials tested proven satisfactory regarding their cytotoxic potential.

1-4

Authors: Manu Rathee

Gingival biotype is of greatest concern in aesthetic reconstructive dentistry, particularly affecting the successful outcome of dental implant placement, periodontal surgeries such as root coverage and ridge augmentation procedures. As gingival biotype has been classified into thick and thin, their applicability into various diagnostic, surgical procedures are hence, must to redaction. The purpose of this article is to provide an overview on gingival biotype and application of available knowledge into practicality.

1-7

Authors: Amal S Al Awdah

Purpose: To investigate the effects of two different forms of sodium ascorbate (solution and gel) as antioxidant surface treatments in reversing the compromised bond strength after vital in-office tooth bleaching with 38% hydrogen peroxide. Materials and Methods: The study included 25 natural teeth (premolars). The crown of each tooth was sectioned in the mesio-distal direction to use both the buccal and lingual enamel surfaces for the bonding procedures. Then, the samples were randomly divided into 5 groups (n=10), according to different treatment options of bleaching and bonding. The specimens were then subjected to a shear bond strength test using a universal testing machine. The modes of bond failure were determined using a stereomicroscope and a digital camera. Results: Bleached enamel immersed in saliva for two weeks before bonding and nonbleached enamel surfaces showed significantly higher bond strengths to composite resin than did enamel surfaces bonded immediately after bleaching without an antioxidant surface treatment (P=.000). There was no significant difference between delaying bonding for two weeks after bleaching and bonding without any bleaching procedure (P=.999). A resin composite bonded to bleached enamel surfaces that were treated with both antioxidants in the different solution forms showed a significantly higher shear bond strength than did a resin composite bonded immediately after bleaching (P=.000). There was no significant difference between the use of sodium ascorbate solution or gel in the shear bond strength (P=.999). It was noted that most the adhesive failures in this study were at the adhesive/resin interface Conclusion: Bonding resin composite immediately after enamel bleaching with 38% hydrogen peroxide reduced the shear bond strength. Both the gel and solution forms of 10% sodium ascorbate can reverse the reduced bond strength after in-office enamel bleaching.

1-5

Authors: Ezgi Atik

A female patient aged 18 years and 4 months referred to dental our clinic with a chief complaint of the unaesthetic appearance of the maxillary anterior teeth and open bite. The maxillary arch was constricted resulting from both the initial cleft and the previous surgical scarring which contributed to bilateral posterior cross bite. The first stage of the orthodontic treatment began with slow maxillary quad-helix expansion appliance. After 4 months of expansion period, asymmetric extractions including upper right and lower left first molar teeth were performed and full fixed 0.022-in Roth prescribed appliances were placed with anchorage appliances to begin aligning and closing the extraction spaces. Active orthodontic treatment was 23 months. At the end of the comprehensive orthodontic treatment of an adult patient with isolated cleft palate, normal function and better esthetics were achieved and the patient was satisfied with the results.

1-2

Authors: Faaiz Alhamdani

Advents in bio-medical technology make us know more about our bodies in health and disease. The more we know the more we ask questions about what we don’t know. To answer these questions we assume (hypothesis). We conduct research to test our hypothesis. Hypothesis testing in experimental setting is the essence of quantitative approach we adopt in bio-medical research. For decades this approach seems to be the only suitable approach to understand facts of our biological system. There are, however, two problems with the quantitative approach in medical research. The first problem is that we deal with the patients on the basis of our assumptions about their health conditions. We seem to ignore the patient’s assumption about their disease within the frame of the life itself. That is why qualitative research is helpful to discover this aspect of patient’s wellbeing. The aim of qualitative research is to develop a concept that helps to understand a social phenomenon in natural setting rather than in an experimental setting [1]. It seeks to explain and understand rather than quantify or predict.