Authors

Dr Saloni Gupta Senior lecturer Dept of Prosthetic dentistry Desh Bhagat Dental College Punjab

Dr Nikhil wazir Oral implantologist HOD and Professor Dept of Operative dentistry Desh Bhagat Dental College Punjab

Abstract

Implant dentistry has seen the most significant growth in the dental field in the last 20 years .There have been  great strides in the area of evidence-based research regarding dental implantology. Understanding of implant histology, biomechanics, occlusion, peri implantology and esthetics has allowed service with extremely long lasting results. There have been advances in dental implants regarding computer aided placement and CAD-CAM technology..In this review article various advances in dental implants have been described.

Key words-implants,,CAD-CAM, Cone Beam Scanning,surgical guide,3 D imaging

Introduction

While dental implants have been around for decades, recent advances in technology and treatment protocols have made treatment more convenient, more effective, and more affordable; making implants the treatment of choice for missing teeth.
Computer guided implant surgery represents a giant step forward in the replacement of teeth with dental implants. With Computerized Tomography (CT) Scan techniques and 3-D imaging, we can now visualize the placement of dental implants in three dimensions. This eliminates the guesswork involved determining what parts of the jawbone offer the best sites for dental implant placement.

CAD/CAM (computer-aided design/computer aided manufacturing) systems have evolved over the last two decades and have been used by dental health professionals for over twenty years .

In 1971, Francois Duret introduced CAD/CAM in restorative dentistry and, in 1983, the first dental CAD/CAM restoration was manufactured.1 Nowadays there is a greater interest in the CAD/CAM systems for implant-supported prosthesis, as they have been used for the manufacture of implant abutments) and diagnostic templates in implant dentistry .In this review article ,various developments in implant dentistry have being discussed.

CAD/CAM abutments in Implant Dentistry

Custom abutments created with CAD/CAM technology have the potential to provide the advantages of both stock and laboratory processed custom abutments without the disadvantages. First, like laboratory-made abutments, CAD/CAM abutments are specific for each patient , however the results are much more consistent.. The virtually designed abutment is electronically transferred to a CAM milling apparatus that creates the abutment from a block of the selected abutment material2. Most of the inherent dimensional inaccuracies of waxing, investing and casting are eliminated. Therefore, CAD/CAM abutments have the potential to provide the most accurate fit of any abutment type.

Commercially available CAD/CAM abutments systems-

1.Cercon
Comprised of the Cercon Eye scanner, Cercon Art CAD design software, Cercon Brain milling unit, and Cercon Heat sintering furnace (figure no-1)

Figure no-1-Cercon CAD CAM System

2.CAD BLU Restoration System
The CAD BLU Restoration System(figure no-2) features the MDX-40ATC wax milling unit, which is capable of milling a single coping in less than 6 minutes using a 98-mm wax disk.

Figure no-2-.CAD BLU CAD CAM system

3.DentalMill
The Digital Dental Lab CAD/CAM system(figure no-3) unites scanning and design software from 3shape, DentMILL CAM software, and the DentalMill milling machine. The DentalMill milling unit comes with an automatic tool measurement, integrated vacuum system, three-button PC interface, touch-screen monitor.

Figure no-3-DentaMill CAD CAM system

 Advantages of CAD-CAM systems-

1. CAD/CAM technology applied to implant surgery allows the production of high resistance and high density crowns3
2. A custom design, a perfect fit and a higher resistance are the main characteristics of CAD/CAM implant abutments.
3. CAD/CAM surgical templates allow to transfer the software planning to the surgical field.

CAD/CAM surgical guides

Placement of dental implants requires precise planning that accounts for anatomic limitations and restorative goals. Diagnosis can be made with the assistance of computerized tomographic scanning, but transfer of planning to the surgical field is limited.
 Recently,novel CAD/CAM techniques such as stereolithographic rapid prototyping have been developed to build surgical guides(Figure no-4) in an attempt to improve precision of implant placement . As a result of this technology, the surgical guide permits accurate and consistent position and orientation of the implants .
Sarment et al.  showed the advantage of this technique in a case-control study that compared the distances between planned implants and actual osteotomies using a conventional surgical guide and a stereolithographic surgical guide.5

Figure no-4-CAD CAM generated surgical template

Computer Aided Implant Placement

Inserting a dental implant is a tricky affair which requires a fair degree of accuracy. It is a highly skilled procedure which requires the dentist to know beforehand the exact position for the implant However, advances in dental technology such as computer aided implant placement have made this much easier to do. Technologies such as Cone Beam Scanning, 3D imaging software and Surgical Guides can achieve extremely high levels of precision that were unheard of a few years ago6.

Cone Beam Scanning (Cone Beam CT)

Cone Beam Computerised Tomography differs from conventional scanning in that it emits a ‘cone beam’ of radiation that captures an entire image, as it revolves around the patient in a single rotation.

Figure no-5- Cone beam scanner generated image showing anatomic landmarks

High resolution 3D images of the teeth and jaw are produced via a series of algorithms. These representations are very accurate and help with implant placement. With cone beam imaging anatomic landmarks (figure no-5) such as foramina and the mandibular canal can be precisely marked, and cross-sectional views accurately show the width and length of available bone,7

Another feature of this scanner is that the patient sits up for the procedure rather than lying down as with the conventional scanner. Lying down tends to result in a collapse of the soft tissues of the mouth which is not the case with the Cone Beam scanner hence the more precise representations.

3D Imaging Software
Imaging software is a very useful tool when planning a course of dental treatment.  It shows a highly realistic 3D representation of the patient’s jaw which can be explored from all angles. The dentist can also place ‘virtual’ implants which enable him/her to check the positioning and make adjustments if necessary.
The implant placement model will consist of precise measurements and positioning which is based upon an individual patient’s anatomical structure.This model is saved and then exported as an email attachment to a dental laboratory. The laboratory will then use this to produce a surgical guide for the actual implant procedure.   .

Summary and conclusions
There are an array of recent advances which are making the dental implant procedure easier and more successful. The use of CAD-CAM dental abutments is one such method. This procedure is extensively used in the manufacturing world to produce intricate and complex components which would otherwise be hard to produce using more traditional methods. New CAD-CAM procedures are making it easier for dentists to build a dental implant abutment which is customized to each of their patients
The Cone Beam CT Scanner is a new dawn in dentistry. From the 3-D images, we can construct exact models of a patient’s jaw and perform surgery on the model prior to performing the surgery on the patient. The result is more accurate planning and surgical treatment. This method reduces the overall time of the implant procedure, minimizes post-operative discomfort, and makes the outcome more accurate and predictable.

REFERENCES

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2.  Ángeles FM ,  Albalat ES. CAD / CAM dental systems in implant dentistry: Update. Med Oral. 2009 Mar 1;14 (3)

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4. Drago CJ. Two new clinical/laboratory protocols for CAD/CAM implant restorations. J Am Dent Assoc. 2006;137:794-800.

5.. Sarment DP, Sukovic P. Accuracy of implant placement with a stereolithographic surgical guide. Int J Oral Maxillofac Implants. 2003;18:571-

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