Biocompatibility of Dental Biomaterials

Richard Shelton

• Publisher: Woodhead Publishing
• Year: 2016
• Print ISBN:
  9780081008843
• eBook ISBN:
  9780081009437
• Topic: Technology & Engineering
• Subtopic: Biotechnology in Medicine
• Index: Technology & Engineering

Biocompatibility of Dental Biomaterials details and examines the fundamentals of biocompatibililty, also including strategies to combat it. As biomaterials used in the mouth are subject to different problems than those associated with the general in vivo environment, this book examines these challenges, presenting the latest research and forward-thinking strategies. - Explores the fundamentals of dental biomaterials and their compatibility - Presents a thorough review of material specific issues

1

Biocompatibility of dental biomaterials

V. Perrotti¹, A. Piattelli¹, A. Quaranta², G. Gómez-Moreno³ and G. Iezzi¹, ¹University “G. d’Annunzio”, Chieti, Italy, ²Oral Health Centre of Western Australia, Nedlands, WA, Australia, ³University of Granada, Granada, Spain

Keywords

Biocompatibility; biological response; interface; human-retrieved implants; biomaterials

Chapter Outline

1.1 Introduction 1

1.2 Measuring the biocompatibility of dental biomaterials 3

References 6

1.1 Introduction

Biocompatibility is the ability of a material to elicit an appropriate biological response to a given application in the body. Biocompatibility is not a property of just the material, but rather a property of how the material reacts with its environment. Indeed, Williams in 2008 defined biocompatibility as: “the ability of a biomaterial to perform its desired function with respect to a medical therapy, without eliciting any undesirable local or systemic effects in the recipient or beneficiary of that therapy, but generating the most appropriate beneficial cellular or tissue response to that specific situation, and optimizing the clinically relevant performance of that therapy.”

The most recent thinking regarding biocompatibility is that it is possible to customize interactions at the material–tissue interface. Therefore, several factors must be considered when trying to measure the biological response. The most important factors include:

Location of the material: this is important to its overall biological response. In general, materials that communicate through the epitheliuim or lie completely beneath it will need closer scrutiny when assessing the biological response than materials that do not penetrate the epithelium. Similarly, materials that penetrate tooth enamel will need more scrutiny than materials than do not. The surroundings of a material can be soft tissue or hard tissue; the material can be exposed directly to the blood, tissue fluids, or saliva, or through a barrier; the material can be placed externally or internally to the oral epithelium.

Duration of material in the body: the duration of the presence of a material in the body is important to the biological response because many interactive effects between the body and material take time to develop. In general, the most stringent tests to measure biocompatibility are required for materials that are present for the longest durations. Long durations give sufficient time for the material to affect the body and for the body to affect the material in many complex ways. What happens when grafted biomaterials and/or dental implants remain in the body for a long time period? Many biomaterials have been proposed in bone regeneration procedures in the oral cavity and in the jaws (Iezzi et al., 2012). Some biomaterials are synthetic, while others have a biologic origin. Some of them, e.g., calcium sulfate, beta-tricalcium phosphate, or polylactic/polyglycolic acid, are resorbed in humans within a few months (3–6 months); however, some biomaterials, e.g. hydroxyapatite, or anorganic bovine bone (ABB), can remain in the grafted healed site for long periods (years or even decades). One of the questions that could be asked concerns a possible negative, untoward effect of the persistence of these biomaterials in the grafted sites on the bone regeneration processes. The long-term fate of some biomaterials is still unknown and the reports present in the literature are not conclusive regarding whether these biomaterials are resorbed over time or not. Different reports can be found regarding the resorption behavior of different biomaterials, e.g. of ABB, one of the most commonly used biomaterials (Perrotti et al., 2009a,b). A group of researchers found that ABB resorbs over time (Galindo-Moreno et al., 2013). The resorption rate of ABB in vivo has been reported to be 2–3 years, and a decrease of about 10% per year has been reported. Other researchers have found that the potential metabolization of ABB by osteoclasts can be confirmed by the progressive increase in relative bone volume. Moreover, it has been reported that the density of ABB decreases by a little more than 10% between 6 and 12 months, suggesting a slow, but active resorption. ABB has been found to become integrated, and subsequently replaced, by newly formed bone. Conversely, other researchers found no signs of ABB resorption even after many years. Our group reported the persistence of biomaterials (hydroxyapatite, ABB) in the grafted sites after many years (7, 9, 14, or even after 2 decades) (Degidi et al., 2013; Iezzi et al., 2007). No untoward effects on bone regeneration processes were ever observed. An ideal material should provide a framework for continuous bone resorption and bone deposition. There is a hypothesis that the presence of graft particles at about 25–30% of the treated site volume may interfere with normal healing, while revascularization and nourishment are deprived, and this could cause problems in the osseointegration of dental implants inserted in these sites. Our histological results of implants inserted in sites regenerated, e.g., with ABB and retrieved after many years (4, 5, 8 years), disprove this notion, because we found in all these case reports a high percentage of bone–implant contact percentage (between 50 and 80%) with mineralized tissue at the interface of these implants even after long loading periods. ABB resorption does not seem to be absolutely necessary to provide predictable osseointegration. The almost complete incorporation of the ABB particles in bone could, how...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• List of Figures
• List of Tables
• List of Contributors
• 1. Biocompatibility of dental biomaterials
• 2. Mechanical biocompatibility of dental materials
• 3. Biocompatibility of fiber-reinforced composites for dental applications
• 4. Biocompatibility of biomaterials for dental tissue repair
• 5. Biocompatibility and functionality of dental restorative materials
• 6. Biocompatibility of luting cements for dental applications
• 7. Biocompatibility of dental amalgams
• 8. Biocompatibility of oral care products
• Index