published_or_final_version / Dentistry / Doctoral / Doctor of Philosophy

The demand for posterior aesthetic restorations has dramatically increased in recent years. Several new materials have been developed with improved aesthetic, adhesive and mechanical properties. However, microleakage elimination, especially if the margins are on dentine or cementum, and attainment of optimum mechanical properties for posterior use, are still questionable. The aim of this study was to investigate microleakage and surface microhardness of a nanofilled, a nanohybrid and an ormocer based nano-ceramic composite restorative material.

<p>Amalgam bonding agents have been shown to enhance retention of amalgam restorations by mechanical means. However, recent studies showed that the use o glass ionomer cements and resin cements as lining and bonding materials to amalgam restorations will increase the retentive strength of the amalgam restorations, hence reducing the micro leakage and secondary caries. The purpose of this study was to compare the relative retentive strength of conventional amalgam restorations and bonded amalgam restorations using resin adhesive, glass ionomer cements and resin cements.</p>

<p>The use of provisional acrylic crowns is common practice with prosthodontic treatment. Provisional crowns are prone to marginal leakage and poor retention due to weak interim cements. The aim of this study was to assess the effect of the application of two different dentine-bonding agents on the microleakage of provisional crowns.</p>

Thesis (Ph.D.)--University of Hong Kong, 1998. / Includes bibliographical references. Also available in print.

Thesis (Ph.D.)--University of Hong Kong, 1998. / Includes bibliographical references. Also available in print.

<p>The objectives of this study were to create an in vitro situation which closest resembled the clinical situation by inclusion of human dentine discs at a specified anatomic location as barrier and evaluating if comparable or graded perfusion could be identified as well as whether a link existed between dentine thickness and permeability. The other leg of the study was to evaluate the cytotoxicity of Xeno III, one of the newly released new generation dentine bonding agents and to evaluate its cytotoxicity in an in vitro pulp chamber device, determining which thickness of dentine would be able to protect the dental pulp from noxious substances in the bonding agent.</p>

The demand for posterior aesthetic restorations has dramatically increased in recent years. Several new materials have been developed with improved aesthetic, adhesive and mechanical properties. However, microleakage elimination, especially if the margins are on dentine or cementum, and attainment of optimum mechanical properties for posterior use, are still questionable. The aim of this study was to investigate microleakage and surface microhardness of a nanofilled, a nanohybrid and an ormocer based nano-ceramic composite restorative material.

<p>The use of provisional acrylic crowns is common practice with prosthodontic treatment. Provisional crowns are prone to marginal leakage and poor retention due to weak interim cements. The aim of this study was to assess the effect of the application of two different dentine-bonding agents on the microleakage of provisional crowns.</p>

<p>Amalgam bonding agents have been shown to enhance retention of amalgam restorations by mechanical means. However, recent studies showed that the use o glass ionomer cements and resin cements as lining and bonding materials to amalgam restorations will increase the retentive strength of the amalgam restorations, hence reducing the micro leakage and secondary caries. The purpose of this study was to compare the relative retentive strength of conventional amalgam restorations and bonded amalgam restorations using resin adhesive, glass ionomer cements and resin cements.</p>