Guided Implant Surgery - The changing language of implant dentistry

DICOM, STL, CAD/CAM, Stereolithography, Guided Implant Surgery.  Implant dentistry has a new language and it has revolutionalized how we treatment plan, place, and restore implants.  Traditional implant surgery consists of the creation of a flap in the gingival tissue in order for the clinician to visualize the bone quantity and quality prior to placement of the implant and suturing.  This is followed by a period of four months of healing prior to the placement of a definitive restoration.  Often times a miscommunication between the surgeon and the restorative dentist results in the misplacement of the implants, resulting in difficulties in final prosthetic design.

The advent of guided implant surgery software has allowed the clinician to treatment plan the implant placement digitally based on the final prosthesis.  It also led to a new language that we use in order to provide minimally invasive surgeries to our patients.  Guided implant surgery is made possible by the utilization of a computer software program that allows us to import DICOM and STL files.  A Digital Imaging and Communications in Medicine file (DICOM) is how we share Computed Tomography (CT) and other radiology data in medicine and dentistry.  With a computer software, the DICOM file which contains radiographic images of the patient's head and neck, a three dimensional image is created.

The software also allows clinicians to import a second data set.  Stereolithography (STL) files are utilized in Computer Assisted Design/Manufacturing and contain tesselations of surface topography data of a three dimentional object, in this case the patient's mouth.  This data is collected from patients in two forms: an intraoral scan of the patient's mouth or the scan of the patient's stone casts made from impressions.  The merging of the DICOM and STL files in the computer software is invaluable because it combines the 3D accuracy of the bone quality and quantity taken from the DICOM file and the precision of the surface topography taken from the STL file. Once merged, a prosthetic can be designed and implants can be placed precisely where the restoration is required.

The last step is to create a file to send to a stereolithography printer for the 3D printing and fabrication of a surgical guide.  Under the same software, a surgical guide can be designed to help the clinician through a seamless workflow that increases the accuracy of implant placement.  Hence, the name Computer Aided Design/Computer Aided Manufacturing (CAD/CAM).  The stereolithography printer also utilizes the STL language which allows the transfer of the 3D topographical information from the design of the surgical guide in the computer software to the reality of the fabrication of a physical guide.  Once printed, sleeves are placed in pre-planned areas in the surgical guide which fit the drilling sequence of the guided surgery with a maximum deviation of 0.2-0.5 mm.  This helps the clinician guage the location, angle, and depth of the implant, avoiding critical structures which may otherwise be damadged.

So how do I do my guided implant surgeries?  The patient undergoes a comprehensive clinical and radiological examination.  Once a proper treatment plan is created and accepted by the patient, an intraoral scan is taken from the patient's mouth utilizing the 3Shape Trios intraoral scanner.  The file output is in an STL format which is saved on my computer.  The patient also receives a Cone Beam Computed Tomography (CBCT) scan with the Prexion scanner which gives me 512 images at 0.15mm increments.  Prexion's own software program puts these images together using a specific algorithm to that machine which gives me a 3D image of the pateint's bone in a DICOM format.  This is also saved on my computer.  Under the 3Shape Implant Studio program, the STL and DICOM files are imported and merged.  A diagnostic wax up of tooth location is completed virtually. Bone quality and quantity are evaluated and implants are virtually placed.  Based on where the implants are placed, a surgical guide is designed and an output in STL format is sent to the ObJet stereolithography printer and a guide is fabricated with a biocompatible material (MED610).  Once printed and cleaned, a sleeve is placed into the guide which will help guide the subsequent surgical drills for the placement of implants.  

The rest is easy!  Predictable, accurate, efficient, and less invasive procedures for my patients.  A full arch of implants can be placed after proper treatment planning in an average of one hour.  Guided implant surgery and CAD/CAM technology has completely revolutionalized dentistry and the way I treat my patients.  It's exciting, and has literally changed my life and the lives of my patients. 

Prosthodontics

Wouldn't it be nice to entrust your smile, your most important asset, to the hands of someone who is properly trained.  Is something we use, we see, we are attracted to, and are judged by not worth the attention to detail a specialist would give?  After treating patients for the past ten years in need of the simplest filling to the most complex implant supported full mouth rehabilitation, I still come across the same set of questions: What is a Prosthodontist?  How are you better trained to treat my complex case?  Is the risk benefit ratio worth the slightly added cost of a detailed diagnosis, treatment plan, and positive outcome beneficial to me in the long run?

A Prosthodontist is a specialist who has undergone three to five years of training beyond the four years of dental school training.  We specialize in comprehensive dental treatment and have gone through extensive training is orofacial aesthetics, reconstructive dentistry, implant dentistry, and disorders of the temporomandibular joint. We treat a wide range of patients in need of fillings, or veneers, or crowns, or implants, and are trained to comprehensively treat patients in need of full mouth rehabilitations.  We care, and we care enought to seek advanced training at higher learning institutes which are accredited by the American Dental Association as specialty programs.  Was the rigorous training worth it?  Absolutely without a doubt yes.  As Aristotle once said, "The more you know, the more you know you don't know."  I practiced general dentistry for four years prior to seeking further education in Prosthodontics, and although I was sufficiently trained to treat my patients, I was constantly hitting a ceiling because of the lack of knowledge.  I thought I knew, but the further I got along in my education, I realized I didn't know.

Throughout my training I came across and was an apprentice to some of the leading clinicians in the world. Something one of my favorite professors once told me has always stuck with me.  Dr. Gary Wetreich who practices Prosthodontics in Wellesley, MA, and teaches at Harvard University leaned forward one day and said, "You're looking at the trees, and I'm looking at the forest."  That's it isnt it?  Prosthodontics is a practice of dentistry that doesn't treat the end result of an unbalanced system, it treats the cause.  For example, a clinician can treat a fractured tooth by placing a crown to replace the missing tooth structure.  However, if you don't look at the forest, the overall system, you migth not realize that the underlying cause of the fractured tooth to begin with was an unbalanced occlusion or bite, which has caused temporomandibular joint problems that may continue even after the fracture has been restored.

Yes, it's worth it to see a specialist, even for that small filling or those veneers you're considering.  Creating that relationship with someone who you can trust and who cares is worth your long term health.  Afterall, your mouth is the gateway to your body, and your smile is the gateway to other's lives and hearts.  Prosthodontists care about the long term outcome of their work and are properly trained to treat simple to complex cases.  Do patients ever wonder who most dentists go to when they're in need of proper treatment planning, comprehensive dental care, aesthetic dentistry, and dental implants?  Yes, it's worth it.