The immediate bonding effectiveness of contemporary adhesives is quite favorable, regardless of the approach used. In the long term, the bonding effectiveness of some adhesives drops dramatically, whereas the bond strengths of other adhesives are more stable. This review examines the fundamental processes that cause the adhesion of biomaterials to enamel and dentin to degrade with time. Non-carious class V clinical trials remain the ultimate test method for the assessment of bonding effectiveness, but in addition to being high-cost, they are time- and labor-consuming, and they provide little information on the true cause of clinical failure. Therefore, several laboratory protocols were developed to predict bond durability. This paper critically appraises methodologies that focus on chemical degradation patterns of hydrolysis and elution of interface components, as well as mechanically oriented test set-ups, such as fatigue and fracture toughness measurements. A correlation of in vitro and in vivo data revealed that, currently, the most validated method to assess adhesion durability involves aging of micro-specimens of biomaterials bonded to either enamel or dentin. After about 3 months, all classes of adhesives exhibited mechanical and morphological evidence of degradation that resembles in vivo aging effects. A comparison of contemporary adhesives revealed that the three-step etch-and-rinse adhesives remain the 'gold standard' in terms of durability. Any kind of simplification in the clinical application procedure results in loss of bonding effectiveness. Only the two-step self-etch adhesives approach the gold standard and do have some additional clinical benefits.

http://www.endoexperience.com/documents/DeMunketalDurabiltyofadhesionJDR.pdf

A Critical Review of the Durability of Adhesion to Tooth Tissue: Methods and Results

Human tissue is structured mainly of self-assembled polymers (proteins) and ceramics (bone minerals), with metals present as trace elements with molecular scale functions. However, metals and their alloys have played a predominant role as structural biomaterials in reconstructive surgery, especially orthopedics, with more recent uses in non-osseous tissues, such as blood vessels. With the successful routine use of a large variety of metal implants clinically, issues associated with long-term maintenance of implant integrity have also emerged. This review focuses on metallic implant biomaterials, identifying and discussing critical issues in their clinical applications, including the systemic toxicity of released metal ions due to corrosion, fatigue failure of structural components due to repeated loading, and wearing of joint replacements due to movement. This is followed by detailed reviews on specific metallic biomaterials made from stainless steels, alloys of cobalt, titanium and magnesium, as well as shape memory alloys of nickel–titanium, silver, tantalum and zirconium. For each, the properties that affect biocompatibility and mechanical integrity (especially corrosion fatigue) are discussed in detail. Finally, the most critical challenges for metallic implant biomaterials are summarized, with emphasis on the most promising approaches and strategies.

Metallic implant biomaterials

Ceramic composites as matrices and scaffolds for drug delivery in tissue engineering.

Tissue-integrated prostheses

Teeth and bones: applications of surface science to dental materials and related biomaterials

Wear: mechanisms, manifestations and measurement. Report of a workshop

Dental materials: 1997 literature review

The tensile strength of composite repairs

The effect of an elevated level of residual monomer on the whitening of a denture base and its physical properties

With the introduction of acrylic resin denture base materials to the dental profession, radiolucency was recognized as a significant deficiency at an early stage. Continuous research into the production of a radiopaque material has been directed at including radiopaque glasses, salts or metals powders in an otherwise radiolucent polymer. However, the majority of new dentures are still made in radiolucent material which is notoriously difficult to locate by conventional radiography and reports continue to appear relating to the inhalation or ingestion of dentures (or fragments of them), occasionally leading to the death of the patient. Advances in radiographic techniques and equipment have seen the development of computed tomography (CT). This has proved invaluable as a diagnostic aid for disease and therapy but little attention appears to have been given to the use of this sophisticated technique in the detection of foreign bodies, in particular those of dental origin. This study investigates the use of CT in the detection of radiolucent denture base material. The results suggest that CT has substantial advantages over conventional radiography in the detection of this material and should be considered as a valuable diagnostic aid in those patients thought to have inhaled dentures or fragments of dentures.

C.H. Lloyd

Papers

Wear: mechanisms, manifestations and measurement. Report of a workshop

Dental materials: 1997 literature review

The tensile strength of composite repairs

The effect of an elevated level of residual monomer on the whitening of a denture base and its physical properties

The use of computed tomography in the detection of radiolucent denture base material in the chest