Technological advances in engineering materials and biological agents continue to provide new potential therapies for patients whose quality of life and physical well-being are affected by severe orofacial defects, tooth loss or the consequences of gum disease. However, getting new therapies into everyday use by dental surgeons is not simple. Currently, only one in every thousand newly developed materials reaches patients, in a process that can take decades, and incurs enormous costs.

Laboratory tests have limited value for assessing the safety and effectiveness of new therapies in people. Tests must also be conducted on animals that resemble humans, both biologically and developmentally. We generally acknowledge that certain animals may be caught and sold, kept in captivity, or eaten, but using animals to meet human needs is as an area of huge controversy. This chapter gives a broad perspective on the ethical basis for animal experiments, drawing from the modern “common sense” view and several longstanding philosophical theories.

All preclinical studies on therapies, procedures and materials intended for use in people must be carried out in accordance with the principles of good laboratory practice (GLP). This chapter gives an overview on the history and scope of GLP, its requirements for the submission of information, and its role in producing safe, high-quality products. Adhering to these principles can be challenging during this era of globalization, especially because different countries have their own regulatory authorities, inspection intervals, legal frameworks and administrative practices.

The findings of studies are of little value without proper statistical analyses that reveal the power of the results, and separate them from events that occur simply by chance. Robust analysis also allows patterns to be observed and comparisons to be made with similar studies. However, the field of statistics can be confusing and overwhelming. This chapter provides an easily understandable summary of the key principles and parameters involved, and the aims of different statistical tests.

These tests are carried out before preclinical studies. They are essential for exploring fundamental responses to procedures such as creating wounds in gum and bone and inserting foreign materials. Success of these interventions depends on the stability of the supporting tissues and the capacity to heal, involving the formation of blood clots and granulation tissue, and the growth of new bone and soft tissue.

Stable soft tissues are essential for the stability of teeth, and patients in need of restorative therapy require a solid foundation for implants. Dental surgeons can graft healthy tissue or insert scaffold material into defective areas to promote regeneration of tissues and stimulate integration. Research has recently focused on the development of new materials that are being tested in preclinical models. Two specific methods are described in this chapter to evaluate the performance of different grafts for gain of keratinized tissue and soft tissue volume. The presented models allow studying tissue integration and regeneration and serve as standardized approaches. The rich information derived this way will make it easier to predict outcomes in humans, and hasten the use of new graft materials in patients.

Animals with defects of the gum can be used to investigate the effectiveness and safety of scaffold materials, devices and biologics for bone and soft tissue repair, before they are tested in people. Living models are essential for observing changes in structure and function over time, sometimes long periods, during the remodeling and healing phases. This chapter recommends which animals are best suited for studying agents such as growth factors and barrier membranes. They include both small and large animals, such as rats, dogs and primates, with both natural defects and surgically or ligature-induced defects.

The complex process of osseointegration involves formation of an interface between a dental implant and the host’s bone, without intervening soft tissue. Formation depends on qualities of the implant surface, such as its roughness and porosity, as well as characteristics of the host. Titanium coatings offer a good osseointegration surface. After preliminary tests to characterize bone-contacting materials and toxicity reactions, animal models are used to assess different aspects of bone remodeling.

The alveolar ridge is the bony tissue that surrounds a fully erupted tooth. Its structure may be compromised after extraction of the tooth, but it can be preserved by use of bone substitutes, dental implants and buccal overbuilding with soft tissue grafts. Ridge preservation techniques must be developed in animals before clinical trials in patients can be conducted, and various processes, such as wound healing, can be explored that are not feasible to study in people.

Ridge augmentation is sometimes needed to establish proper soft and hard tissue support before placing a dental implant. The horizontal augmentation procedure is commonly used in dental clinics to restore bone defects in people with destructive gum disease. There are many variables to investigate to optimize these treatments, for which several animal models exist.

Vertical augmentation is essential for restoring bone defects in patients with destructive gum disease, before rigid fixation of implants or grafts. However, in practice it is associated with high complication rates and limited success. Thus it is important to refine the techniques used by dental surgeons through preclinical research. This chapter looks at various animal studies, and focuses on one specific validated, reproducible and reliable protocol.

The maxillary sinuses are located inside the cheekbones, above the upper jaw, from the second premolar area to the wisdom teeth. In some people with tooth loss, the sinuses are too close to the upper jaw for dental implants to be placed; in others, bone may have been reabsorbed because of gum disease. In either case, bone height can be restored using a sinus lift – an increasingly common technique in dental practice.

Inserting implants immediately after tooth extraction reduces clinic appointments, but some patients experience breakdown of their gum and bone tissues; this early exposure of the implant inhibits bone regeneration and implant success. Increasing numbers of people have implants nowadays, more of which contain titanium, which is good for osseointegration, but tends to harbor bacteria if the surrounding bone shrinks away.

The bone healing process in people can be affected by diseases such as Crohn’s disease, diabetes and colitis. It can also be affected by drugs such as bisphosphonates, which are used to treat weak bones in people with osteoporosis, Paget's disease and certain cancers. The role of animal models is enormous for investigating these disease conditions as well as other “risk factors” for compromised healing, such as radiotherapy, which is being increasingly used as early treatment of cancer in the community rises.