# Ten Years of Micro-CT in Density and Maxillofacial Surgery: A Literature Overview
## 1 Introduction  
The first X-ray microtomography or micro-computed tomography (micro-CT) system was conceived in the early 1980's, and in 1994, the first commercially available bone micro-CT scanner was presented [1, 2]. Nowadays, micro-CT systems are present as lab instrumentations at main laboratories and companies to perform different types of investigations and for various applications, including educational purposes [3, 4]. Micro-CT represents one of the main methods to perform non-destructive analysis and one of the most common microscopy methods [5] where the very fine scale internal structure of objects is imaged, providing high resolution volumetric data at a micron level. It allows for the investigation of microstructures, the accuracy detection of the geometries [6, 7, 8, 9], eventually defects and difference in density and morphology. It does not require specimen preparation, staining and slicing; settings and parameters were extensively studied for specific structures [10]. It has great potential for biomedical and bioengineering applications [11]. The analyses carried out by micro-CT can be helpful also in terms of compliance to international standards, regulations, and in forensic practice [12, 13]. Microtomographic analyses can affect the validation process of materials and the quality assessment of final devices. Recently, in the medical device sector, the growing interest in emerging manufacturing techniques as the additive ones, allowed to recognize micro-CT as one of the major tools for the product quality assessment and for the quality control of additive manufacturing (AM) products and materials [6, 14, 15, 16]. Denistry and maxillofacial surgery (MFS) represent two sectors that affect the biomedical engineering context and in which there was an extensive use of the micro-CT due to the necessity to acquire detailed information of small and complex objects, mineralized structures [17; 18; 19], and with different densities. The market is characterized by innovative materials and solutions that require advanced technology in routine-based activity of dental labs and clinics as the micro-CT scanning [20], whose capabilities turn out to be indispensable [21; 22; 23]. The authors have extensive knowledge and experience about micro-CT and its application in biomedical studies and in both fields addressed here [6; 7; 24; 25; 26; 27; 28; 29; 30; 31]. Specifically, in this work, the first author ([PERSON]) independently reviewed and organized the records identified from the database searches to assess the initial eligibility and both the authors ([PERSON] and [PERSON]) fully reviewed the search results. Disagreements were resolved by reaching a consensus or consulting the third and senior author ([PERSON]). In the early 2000's, [PERSON] believed in such technology and had engaged many research funds in the purchase of equipment to perform three-dimensional (3D) microtomography and to undertake research collaborations to study the effectiveness of this 3D methodology compared to the traditional ones, such as histology and electron microscopy [7; 8; 15; 24; 25; 26; 27; 28; 30; 31; 32]. The aim of the present paper is to deliver a structured overview of the literature, highlighting the main applications of micro-CT in dentistry and MFS, and considering the set of articles published in English from 2010 to January 2020 in PubMed/MEDLINE and Scopus (excluding Medline records from search results). A primary search was based on the following set of keywords: (i) (\"micro-computed tomograph\" OR micro-CT) AND (dentistry OR \"maxillofacial surgery\") for--Title, Abstracts, and Keywords. A secondary search was performed in MEDLINE on this set of keywords: (ii) (micro-computed tomography OR micro-CT) AND (dentistry OR maxillofacial) for All Fields and applying a filter limiting to the type of study \"Review\".