New Protocol For NTI-Plus Appliance Is Predictable and Profitable By:

Over the course of our careers, we have and will be introduced to many new techniques and procedures. Once we have accepted them as valuable and traversed the learning curve of utilization, the next question is invariably how can we be more efficient in this procedure? After a few years of chairside NTI use that question again was raised. Like many practitioners, I felt I had become quite efficient in the chairside fabrication of NTI devices. Fabrication had become routine, patient compliance was high and the success our patients experienced in treatment was quite remarkable. So, why change?

Keller Laboratories and Dr. Jim Boyd, inventor of the NTI-tss device, have joined forces to provide the NTI-Plus, a lab fabricated NTI device for practitioners who might not be interested in the process of chairside fabrication of the NTI appliance. As I had been involved with developing and refining medical billing protocols for the NTI, Dr. Boyd and Keller asked me to put the NTI-Plus through its paces.

The initial process seemed simple enough: take an upper and lower impression and send them off to the lab. About 10 days later, a beautiful, crystal clear NTI was returned. While this method was simple, it did not adequately communicate the vertical dimension of the discluding element (DE) necessary for canine and posterior disclusion or the patient’s anterior/posterior range of motion. While several of the devices required no adjustment upon delivery, there were those that required reduction or addition of acrylic. With the help of Dr. Boyd and Keller Laboratories, I developed the following protocol as an evolution intended to make the NTI-Plus more predictable, efficient and profitable for practitioners. In many cases, the lab fabricated NTI-Plus can actually exceed the chairside fabricated device in each of these categories.

The NTI-Plus Protocol involves four simple steps. First, a measurement must be taken to determine the vertical dimension of the DE required to allow for disclusion of the canines and all posterior teeth, which is essential for successful NTI therapy. Using a calibrated leaf gauge (Great Lakes Orthodontics), this vertical dimension of disclusion is determined in all excursive movements (Fig. 1). The leaf gauge is calibrated to .1mm increments, with each millimeter leaf a bit longer to allow for easy measurement. It is important that the patient simply rest on the gauge as biting into it will displace the leaves and the mandible, making the measurement inaccurate.

Fig. 1

Fig. 2

The second step involves recording the maximum protrusive of motion the patient can accomplish and recording the inter-incisal distance (Fig. 2). This can be accomplished using the TMJ Triangle (The Pankey Institute Bookstore) or any rigid plastic ruler with raised markings. Add 2mm to this measurement (e.g. 6mm+2mm protrusive) to allow an additional range of motion that the patient may experience through the benefits of therapy. This will communicate the extent of the discluding element necessary to prevent the patient from getting in front of it. (It does not seem necessary to communicate the retrusive measurement as there is sufficient acrylic in the NTI design to accommodate for minimal retrusive movement).

The third step involves taking an anterior triple tray in polyvinylsiloxane (PVS). Full arch impressions are not necessary as the vertical dimension of disclusion has already been communicated. The anterior triple tray from Exacta (Fig. 3) is an excellent choice for this technique as the extended vestibular design aids in capturing not only the dentition, but also the supporting tissues (Fig. 4). This is critical as the NTI is extended apical to the CEJ for retention. Two good choices for the impression material are Status Blue from Zenith DMG and Position Penta Quick from 3M (Fig. 5). Both are an economical alternative to standard crown and bridge impression materials and available for use in bulk, auto mix units (Mixstar, Zenith DMG; Pentamix 2, 3M).

Fig. 3

Fig. 4

The final step is to communicate to the lab whether you desire a maxillary or mandibular appliance. While opinions vary, excellent results can be achieved with either. It has been my experience that mandibular appliances require less adjustment to the lateral aspect of the DE to prevent canine contact than maxillary counterpart. In our practice, patients have also reported greater comfort with mandibular devices.

This information and the impression are then sent to Keller Laboratories and in about ten days, you will receive back in your office an exquisite NTI-Plus that should require little to no adjustments (Fig. 6). Because of the extreme accuracy in the fabrication process, minor internal adjustments may be necessary in the interproximal areas. This can be accomplished in just a minute or two with a lab scalpel.

Fig. 5

Fig. 6

Following this protocol, the initial measurements and impression can be taken in approximately three minutes and delivery accomplished in under five minutes. Having spoken with numerous practitioners, chairside fabrication of the NTI device tended to range from 20-30 minutes in an efficient office. A common production goal in many offices surveyed was $500/ doctor hour ($8.33/minute). Given the time-savings of 12-22 minutes saved in fabrication, the lab expenditure (-$100) can actually be more economical. (Many offices may be comfortable delegating these protocol procedures, while they may not be regarding actual fabrication.)

The NTI has been a valuable treatment tool in my practice for several years. With this protocol, I have added the NTI-Plus to my treatment toolbox. Keller will soon have revised prescription forms available to record the information from this protocol as well as a laminated, step-by-step photo card that can be kept available in the operatory. With the increased efficiency and profitability the NTI-Plus offers, I hope dentists everywhere will find this protocol very beneficial in their own practice.

---

Dr. Mike Melkers has developed this protocol for Keller Laboratories and is involved with medical insurance issues regarding the NTI-tss appliance. Dr. Melkers has presented programs on the NTI, articulation, lab communication and other occlusion-related topics around the nation, including as a faculty member of the Ultimate Occlusion Program at Pac~Live. While Dr. Melkers has received product support from NTI-tss Inc., Keller Laboratories, as well as the other companies mentioned in this article, he declares no financial interest in any of the companies. Dr. Melkers can be contacted at DrMelkers@aol.com.