ABSTRACT
This chapter provides a survey of titanium, today’s most frequently used material in oral and maxillofacial surgery for internal fixation of fractures and osteotomies, as well as to bridge bone defects after tumor resections in the form of plates and screws. The chapter is introduced with a survey of bone morphology, healing, and characteristics of facial bones. Surgical treatment changes due to the advent of plates and screws are highlighted. The development of nonresorbable materials for internal fixation is described in chronological order; their concomitant adverse effects are pointed out. Titanium as the current number one rigid internal fixation material relishes a closer insight. First a summary of its chemical and mechanical properties as well as a brief discussion about
its biocompatibility are presented. After a survey about clinical applications of titanium plates and screws in oral and maxillofacial surgery, the to date resorbable alternative material poly (α-hydroxyacid) is shortly presented. Plates and screws of this material are mainly used in craniofacial surgery. 13.1 IntroductionRelated to reconstructive procedures after fractures and tumor resections, the oral and maxillofacial area represents a challenge both to surgeons and to material. Due to the following reasons surgeons have to choose the most appropriate biocompatible material for internal fixation: firstly bone structures vary from thin and delicate in the midfacial region to thick and hard in the mandibular cranial regions, secondly biting and chewing forces represent mechanical stresses to materials being used for internal fixation, and thirdly, in many oral and maxillofacial regions internal fixation materials are only covered by thin, soft tissue layers [1]. Due to its mechanical and chemical properties, its relative low toxicity, and sensitization titanium represents since the mid-1980s a reliable and safe material to master these challenges [2, 3]. 13.1.1 BoneBone is the supporting tissue of our body, which determines its form and size. Its hardness is mainly a result of its 65% nonorganic content of hydroxyapatite. However, due to the high amount of collagen, which accounts to around 95% of the organic matrix, bone is elastic. Every impact of force that exceeds the bone’s own elasticity results in a break, called fracture. It is important to know that bone is a dynamic tissue with a usually balanced apposition and resorption rate. This balance is steered by physiological and mechanical factors. According to their localization, facial bones vary in thickness and strength. Whereas thick in the mandible and frontal areas, lamella-like thin bones are found in the midfacial area; these are integrated in a honeycomb-like framework of bony pillars.
