Rapid prototyping in dentistry: technology and application

ABSTRACT:
Dental care and dental treatments have become very common these days and as per a survey around 500 million dental visits are made each year by 66% of the total US population. Almost all dental treatments involve a cascade of steps that are needs to be carried out with high level of accuracy to avoid failure of prosthesis because of some manual or technical error. With the introduction of Rapid prototyping there is more scope of procuring more complex parts with comparatively minimum technology and skill with high accuracy and very less error. Rapid prototyping although initially developed to be implemented in industries that manufacture turbines, surgical equipment and aerospace parts. Now some researchers have seen the advantages of Rapid prototyping used in dental applications. In this review paper an effort is made to learn to the scope of implementing different rapid prototyping processes that can be used in dental applications by studying the some researches that are taking place regarding this.

INTRODUCTION:
Prosthetic dentistry is a branch of dentistry that is specialty concerned with the making of artificial replacements for missing parts of the mouth and jaw. Everyday prosthodontics involves cascade of steps that are needs to be carried out with high level of accuracy to avoid failure of prosthesis because of some manual or technical error. So this process is highly technique sensitive and time consuming.
After the introduction of Computer Aided Designing (CAD), and Computer Aided Manufacturing (CAM) and laser technology revolution has happened in the field of manufacturing technology which was known as Rapid prototyping (RP). The aim of RP is to create products within shorter time, and with more accuracy without human errors.
WHAT IS RAPID PROTOTYPING?
Rapid prototyping (RP) is potential tool in modern technology and refers to a process of manufacturing computer-generated models by adding consecutive layers of material to build a physical 3D object.
Rapid prototyping although initially developed for engineering, product development environment has found its place in almost all areas of our lives. One of the most exciting applications of RP is in medical field often referred as rapid bio-modelling or rapid bio-prototyping.
DENTAL APPLICATIONS:
Almost all the dental treatments requires an model of current dental state of the patient which can be done by using RP.RP technology can be used to make a series of essentially invisible orthodontic prosthesis for straightening teeth. It can be used to produce 3-D representations of focal bony structures using data from CT or MRI. It can also used for presurgical planning of implant placement. In restorative dentistry for fabrication inlays, on-lays crowns. etc.
CONVENTIONAL DENTAL APPROACH:

Figure 1: Process in fabricating precise dental model
Traditional dental approach as seen in [Figure 1] involved taking impression of the patient part using the impression to make a master model then following by a series of processes like Wax up ,Mould preparation, casting, devesting , preparation, veneering and the implementing it to the patient. In conventional approach all these steps were done manually and needed high skill.
RAPID PROTOTYPING APPROACH:

Figure 2: Flowchart of the working process of rapid prototyping.
The initial condition of patient was take either by traditional impression method or by no-impression methods to capture data such as Computerized Tomography (CT) and Magnetic Resonance Imaging (MRI).Then the captured data is used in the creation of CAD model .This cad model is then converted into STL file followed by slicing of stl file into layers. Then the model or the part is built one layer at a time adopting any of the technologies available and the Post processing is done and finally the part is used for the treatment. A flowchart of the working process of Rapid Prototyping is show in Figure