Written by Richard A. Mecall, DDS, MS Thursday, 31 December 2009 19:00
I have lectured internationally about computer-guided implant treatment since 1989 and have contributed to the development of implant treatment-planning software. During my travels and in teaching others, I hear the following comments: (1) “It’s too difficult!”; (2) “It takes too much time!”; (3) “It’s too expensive!”; and (4) “I do a good enough job without it.”
While I can appreciate the above comments, the same could be said about adhesive dentistry, endodontic microscopy, and CAD/CAM restorations. Each of these technologies has revolutionized dentistry, allowing dentists to achieve excellent minimally invasive results and to better fulfill patient’s needs and concerns.
This case report demonstrates the use of a universal implant treatment planning algorithm in response to the above comments. The techniques presented enable both experienced and inexperienced dentists to achieve comparable treatment outcomes.
The most important phase of computer-guided implant treatment is the diagnostics. A standardized method for analyzing diagnostic information is essential when developing a computer-guided treatment plan.1 Diagnostic inquiries can be divided into 3 types: addressing these inquiries is essential prior to building a scanning appliance, completing a computed tomography (CT) treatment plan, or ordering a surgical guide for implant placement.
COMMENT NO. 1: “IT’S TOO DIFFICULT!”
As dentists, we are all familiar with abnormalities that include but are not limited to repose tooth display, full-smile tooth display, tooth proportions, and incisal/posterior occlusal plane irregularities.2 We are using the same decision-making skills that are the centerpiece of traditional dentistry. The vehicle for transitioning a patient, from how they present to how they see their final treatment outcome, is the diagnostic wax-up.
If all of the diagnostic inquiries have been addressed, the diagnostic wax-up and scan appliance should serve as a replica of the final restoration (Table 1).
COMMENT NO. 2 “IT TAKES TOO MUCH TIME!”
Today, dental laboratory diagnostics, virtual implant treatment planning, and construction of a provisional restoration can all be outsourced so that the dentist can continue to treat patients. Since decision making has occurred preoperatively, the actual surgical time is reduced. In fact, many of the surgical procedures can be complete using a flapless surgical approach. Lastly, the provisional restoration has been fabricated prior to surgery, which reduces the time to complete adjunctive restorative procedures at the time of surgery.
COMMENT NO. 3: “IT’S TOO EXPENSIVE!”
With the understanding that the use of a CT Scan is the standard of care for dental implant procedures in most regions of this country, the paradigm that computer-guided surgery is too costly is simply not true. The only additional cost, when compared to manual implant placement, is the surgical guide. All of the remaining costs are the same for manual versus guided-implant placement.
COMMENT NO. 4: “I DO A GOOD ENOUGH JOB WITHOUT IT.”
Computer-guided implant placement is the only method to precisely transfer information from a diagnostic wax-up to a 3-dimensional radiograph, merging both the surgical and prosthetic information into one digital document. All decision making occurs prior to surgery. The surgical guide becomes the conduit between prosthetic evaluation, implant treatment planning, and the final restoration. No other method of implant treatment can precisely control implant depth and implant angulation. Lastly, computer-guided implant placement is the only approach that allows the dentist to assist the patient in making an informed preoperative healthcare decision and accurately determine the cost of treatment.3
A 45-year-old female patient presented for replacement of her missing maxillary anterior teeth, Nos. 7 to 10, secondary to acute trauma resulting from a car accident (Figure 1). The patient reported difficulty during speech and mastication. She desired an aesthetic fixed restoration to replace the missing teeth.
|Figure 1. Ovate pontic design of interim removable prosthesis has created soft tissue receptor sites with optimal form and depth. The diagnostic wax-up and scan appliance will transfer the ridge architecture to the computed tomography scan, providing guidance for implant positioning during treatment planning.||
Figure 2. Note the volume of tissue visible coronal to the high lip-line. While the high lip-line provides guidance, in terms of marginal gingival position, the amount of soft tissue below the lip establishes the level of predictability in creating optimal interproximal form.
It was decided to place an interim removable prosthesis with ovate pontic design to replace these teeth. Facial symmetry, lip symmetry, and nasolabial angle were all within normal limits. Lip movement in full smile revealed 3 mm of residual ridge (Figure 2), thus allowing for the development of an acceptable emergence profile. The consultation included a treatment plan for an implant-supported restoration with CT-guided surgery to provide a laboratory-processed provisional restoration that could be delivered at the time of implant placement.
Scan Appliance Fabrication
Impressions were made and diagnostic casts mounted in a repeatable treatment position. A diagnostic wax up with acceptable tooth proportions was completed and served as a template for fabrication of the scan appliance (Figure 3). The scan appliance was then constructed using clear acrylic (Polymethylmethacrylate [Lang Dental]) with registration markers following the NobelGuide (Nobel Biocare) protocol. A radiolucent bite record was made in a Denar Combi II Articulator (Whip Mix) and confirmed in the patient’s mouth (Figure 4).
|Figure 3. The diagnostic wax-up has been completed, becoming the template (replica) of the final restoration.||Figure 4. The scan appliance has been constructed from the diagnostic wax-up. The intermaxillary relationship has been maintained during the scanning process with the use of a radiolucent bite record in a repeatable treatment position. The bite record is made in the articulator by dropping the incisal pin 2 mm to 3 mm.|
The diagnostic wax-up, scan appliance fabrication, provisional restoration and final restoration are all completed by well-trained dental laboratory technicians. This allows the dentist who embraces computer-guided implant treatment to continue to treat patients and generate an income stream.
Computed Tomography Scan (Spiral or Cone-Beam)
Using the Nobel guide treatment planning software, CT treatment planning is completed following an 8-step protocol (Table 2).3
When the surgical guide is manufactured, it is used to create a master model for fabrication of the provisional restoration. This provides the dentist with another opportunity to verify the accuracy of treatment plan as it relates to the prosthesis (Figure 5). All of the CT treatment planning and surgical guide construction can be outsourced (Guide U to Success at guidingutosuccess.com) so that you can be mentored one-on-one, review and approve the plan, and order the guide and implant components needed for the provisional and surgical phases. If you consider that the dentist continues to produce an income stream, and the treatment time is reduced (while all of the diagnostic work is being completed and at time of surgery), you can easily see how computer-guided placement can be a profitable in-office procedure.
Figure 5. The implant master model has been constructed using the surgical guide. This provides the dentist with the final opportunity to evaluate implant position related to the interim or final prosthesis.
Figure 6. The surgical guide has been inserted. Fixation has been achieved with ligature wire. All surgical guides should be fixated even for single-tooth implants
Figure 7. The provisional restoration was placed at the time of implant placement. There is no occlusal contact in excursive or centric positions.
|Figures 8 and 9. The final restoration was constructed 3 months later. A new implant level impression was made and custom abutments were fabricated to optimize emergence profile.|
Surgical treatment is now completed and consists of surgical guide insertion and fixation, osteotomy site preparation, and insertion of the provisional restoration (Figures 6 and 7).
Final restorative treatment was completed 3 months following surgical treatment. An implant level impression was made and custom abutments designed to optimal emergence profile of the restoration (Figures 8 and 9).
This case report demonstrated the use of CT-guided implant surgery in an area with anatomic limitations. The treatment plan provided for the placement of 2 implants with immediate provisionalization, predictability, and precision.
- Mecall R. Computer-guided implant treatment pathway. In: Tardieu PB, Rosenfeld AL, eds. The Art of Computer-Guided Implantology. Chicago, Ill: Quintessence Publishing; 2009: chapter 7, 89-112.
- Spear F. State-of-the-Art Esthetics [audio CD]. The Seattle Institute for Advanced Dental Education; 2005.
- Mecall R, Rosenfeld A. Use of prosthesis-generated computerized tomographic information for diagnosis and surgical treatment planning. In: Rothman SLG, eds. Dental Applications of Computerized Tomography: Surgical Planning for Implant Placement. Chicago, Ill: Quintessence Publishing; 1998: chapter 9, 177.
Disclosure: Dr Mecall is the founder of Guide U to Success, Inc. He acted as a consultant in the development of early SimPlant versions. Since 1987 he has provided computer-guided implant treatment planning courses for Materialise, USA, Sirona, and Biomet 3i. Most recently, Dr. Mecall has developed a universal implant treatment algorithm for computer-guided implant treatment planning allowing any dentist to use SimPlant to more easily treatment plan surgical and restorative implant treatment.
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