Abstract

Dental implants have proved to be an acceptable alternative to conventional crown and bridge restorations. In many cases, multiple edentulous sites have been restored by splinting multiple implants. This provided strength and stability for the final prosthesis. With the advent of the Frialit®-2 Implant System, an internally retained system, sequential free-standing crowns can be predictably treatment planned. This article describes the case of a patient requiring sequential single-tooth implant restorations.

The Frialit®-2 Dental Implant Systema is the only dental implant that maintains the stepped-cylinder concept of the Tuebingen implanta used and clinically documented since 1976.(1) The Frialit®-2 system (introduced in 1992) converts the implant process to a two-stage surgical procedure, optimizes immediate implantation opportunities, and offers prefabricated superstructure components that yield optimum function and esthetics.

The Frialit®-2 Dental Implant Systema is the only dental implant that maintains the stepped-cylinder concept of the Tuebingen implanta used and clinically documented since 1976.(1) The Frialit®-2 system (introduced in 1992) converts the implant process to a two-stage surgical procedure, optimizes immediate implantation opportunities, and offers prefabricated superstructure components that yield optimum function and esthetics.

Advantages

The Frialit®-2 system offers the following four advantages, making it the system of choice for many implant dentists: (1) reliable implantation and osseointegration; (2) superior engineering; (3) optimum esthetics; and (4) increased treatment compliance with oral hygiene maintenance.

Learning Objectives

After reading this article, thereader should be able to:

• discuss the surgical, laboratory, and prosthetic applications for the implant system described.
• improve final prosthetic results with proper preparation before surgical placement.
• treatment-plan single dental implants with predictable results.

Reliable Implantation and Osseointegration

Because of this system's precisely fitting, internally irrigated drills with depth stops, the restoring dentist and the laboratory technician can plan on reliable implantation. The two-stage surgical procedure and the pure titanium Frios®-coated implant guarantee undisturbed implant osseointegration. 2 This provides optimal opportunity for immediate and immediate-delayed implant placement, increasing primary stability of the implant even in poor-quality bone.

Because of this system's precisely fitting, internally irrigated drills with depth stops, the restoring dentist and the laboratory technician can plan on reliable implantation. The two-stage surgical procedure and the pure titanium Frios®-coated implant guarantee undisturbed implant osseointegration. 2 This provides optimal opportunity for immediate and immediate-delayed implant placement, increasing primary stability of the implant even in poor-quality bone.

Superior Engineering

As a result of years of scientific and clinical research, the wide diameter of the root analog of the implant and accurately matched collar heights yield optimal results in an emergence profile that produces superior functional and esthetic results.2 At the same time, the Frialit-2 system minimizes the load transfer with its tooth analog implant shape, and the epithelial integrity is both protected and maintained as a result of the transmucosal implant/abutment design.

Prefabricated superstructure components are offered for the entire range of prosthetic needs. The interhexagonal superstructure of the implant is completely rotation-stable, and the cylinders above and below the interhexagon feature provide stability. All system components are color-coded according to the implant diameter. In response to the concern of microleakage, Frialit-2 is the only dental implant that offers a silicone hermetic seal between the abutment and the implant.

Optimum Esthetics

The anatomically shaped implant allows tooth-by-tooth restoration in multiple single units. The following clinical reconstruction comprises four single implant units. This is a procedure that, until now, implant dentistry has been unable to predictably provide.

Increased Patient Compliance With Oral Hygiene Maintenance

The various diameters of implants in the Frialit-2 system yield an ideal emergence profile, which translates into superior function and esthetics and ease in patient home-care procedures.

Case Report

The patient, a 60-year-old man with an unremarkable medical history, presented with a blade implant that had been placed approximately 20 years ago (Figure 1). The implant became mobile and required surgical extraction, leaving the mandibular bicuspid and molar region edentulous (Figure 2). After examination, the proposed treatment plans included the following options:

1. a conventional removable partial denture replacing the missing teeth;
2. several dental implants supporting a splinted bridge;
3. single-tooth replacements using the Frialit-2 Dental Implant System.

The patient selected the third option involving single-tooth replacements, and a computed tomography (CT) scan was completed and placed in the computer program to map the exact location of the proposed implants. The system used was Sim/Plantu,b.

The anatomy is visible in three dimensions, which allows the schematic positioning of the implants before performing any invasive surgery (Figure 3). In this way, the correct angulation and size including length and width of the implant can be determined preoperatively.

First Surgical Stage: Implantation

The first surgical stage involves implantation. The Frialit-2 Implant System offers four different implant diameters corresponding to the different cervical anatomic contours and dimensions. It was the first implant system to anadonically oxidize a color-coded system to ensure that all components can be easily and reliably matched to the corresponding implant.

The Frialit-2 instrument set is comprised of a 2- mm and a 3-mm diameter spiral drill, a 3.8-mm-diameter round bur, and stepped drills corresponding in diameter and length to the implants. The system includes both internally and externally irrigated drills (Figure 4).

A clear prefabricated surgical template or stent is used to direct each implant placement. Occlusal openings have been made within the stent that allow for proper and consistent implant adaptation (Figure 5).

A releasing incision is made, and the flap is easily elevated. Care is taken not to damage the tissues in any way. The vital anatomy (the mental foramen and nerve) is exposed (Figure 6). Their position will dictate the correct angulation and position of the implant. With the crestal ridge exposed, the surgical stent is repositioned, allowing the clinician to clearly see where the implant should be placed.

The occlusal openings in the stent allow the surgical bur to be angled correctly. A 2-mm spiral drill is used to make the first opening within the bone (Figure 7). The ideal bur speed with the spiral and stepped drills is 800 rpm to 1000 rpm, using copious internal irrigation.

Angulation

Angulation of the bur is critical. Staff can assist in visualizing angulation in additional dimensions. The use of paralleling pins allows for the visualization of proper angulation and correct implant placement before making the final implant-receptor site (Figure 8). The angulation of the implant must follow the preoperative work-up, as well as the angulation of the natural teeth. As the patient occludes over the paralleling pins, proper occlusal direction of the pins can be further evaluated. The 2-mm spiral drill is then taken to the predetermined depth. To ensure maximum safety when implanting, all instruments have interior irrigation and a depth stop.

If any irregularities in the alveolar ridge necessitate a deeper receptor site, as in this case on the mesial of the first premolar, the depth stop can be removed. The remaining three implant sites had ideal ridge contour for use with the Frialit-2 depth stop in place. The 3-mm spiral drill enlarges the opening along the angulation determined by the 2-mm spiral drill. The process is repeated for the number of implants planned.

A 3.8-mm round bur is used to countersink the crestal bone. This provides a purchase point for subsequent drills. Parallel pins are again used to check the final long axis position. This process is repeated for the number of implants planned.

In this surgery, the receptor site is prepared to the final diameter by using stepped drills of successive increasing sizes (3.8 mm, 4.5 mm, 5.5 mm, or 6.5 mm). In this case, the procedure stopped with the 4.5-mm diameter stepped drill as predetermined by the CT scan, and the procedure was repeated for the number of implants planned. With the larger diameter implant, the 3.8-mm stepped drill is not used in the succession of drills. Rather, the clinician would use the 3 mmbur and then move directly to the 4.5-, 5.5-, or 6.5-mm stepped drill to prepare the receptor site (Figure 9).

The osteotomy sites are rechecked with the surgical stent. Without breaking the sterile chain, the implant is removed from the sterile packaging and placed in the cavity up to the lower edge of the uppermost section, using finger pressure only. A mallet is used to lightly tap the inserting instrument and placement head until the implant fits snugly and can be rotated into place (Figure 10). The placement head is removed, the placement instrument for stepped screws is inserted into the interhexagon of the implant, and the ratchet are placed into position. Three full turns of the ratchet is sufficient to place the implant into its final position (Figure 11).

After implant insertion, the corresponding color-coded sealing screw is threaded into position (Figure 12). Placement is verified with the surgical stent. The mucosa is drawn over the implant with interrupted and mattress sutures. The importance of suturing cannot be overemphasized in an implant procedure. A tight closure helps ensure that the sutures will not break, and that the tissues will remain in close proximity to each other (Figure 13).

Second Surgical Stage: Recovering the Implants, Sealing, and Impressions

After a 4-month healing period, the implants are recovered with a tissue punch (Figure 14). The titanium sealing screws are removed and replaced with a gingival former. The gingival former enables the gingival margin to form properly during the healing period. This ensures that as soon as the crown abutment has been inserted, the gingiva will be in close contact with the collar of the abutment, providing a bacteria-proof seal.

Gingival formers are available to fit the four implant diameters at 1-mm to 2-mm, 1-mm to 3-mm, and 5-mm collar heights. The highly polished, wide-diameter Frialit-2 gingival former promotes healthy and ideally contoured tissue.

When the gingiva has healed, the gingival former is unthreaded and replaced with the transfer coping. Frialit-2 transfer copings, for transferring the position of the implant exactly and reliably to the master model, are available to fit the four implant diameters. Two flat, parallel surfaces on the transfer coping exactly transfer the position of the hexagon (Figures 15A and 15B). A circumferential groove ensures that it is repositioned correctly in the vertical dimension.

The transfer coping is inserted into the interhexagon of the implant with a No. 4305 coping screwa. This procedure is repeated for all implants planned. Corresponding color-coded transfer caps are inserted onto each coping. These allow for better transfer of the impression coping back into the impression. In this case, there was inadequate space for placement of the most posterior transfer cap. The screw chamber opening in this case was covered with utility wax to prevent the impression material from flowing into the chamber.

Taking the Impression

A custom tray was fabricated for the impression phase. A vinyl polysiloxane medium-body impression material was placed around the transfer impression copings, and a heavy-body material was placed within the tray. Polyether impression materials are acceptable alternatives. A firm impression material will produce the most accurate impression. After the impression is removed from the mouth, the transfer coping is removed and placed within the impression to verify that its coping fits firmly back into the impression. The case is now ready to be sent to the laboratory.

The Master Cast

The master impression received from the restorative dentist will have been injected with a regular- or heavy-body elastic material around the impression coping.A good seat between the coping and the analog can be verified by uniting the implant analog with the implant coping and securing it with the fastening screw.

By lining up the flats of the impression coping with the corresponding flats in the impression, the assembly is rotated and snapped into position. Each analog and coping are placed into their corresponding position, and the master cast is poured.

After the master cast has been prepared, the case is mounted on a semiadjustable articulator. In some instances, the height of the impression coping does not allow for the articulation of the casts. In this case, the mandibular impression coping was removed for this procedure.

As you will note, the alignment of all implants is quite vertical. This indicates that the selection for the corresponding abutment will be the straight abutments. An angled abutment is not necessary.

Abutment Selection and Modification

All of the parts in the Frialit-2 Dental Implant System are color coded. The impression coping, analog, and the abutments are color coded to the diameter of the implant.

One of the primary mechanical benefits of the Frialit-2 system is the internal antirotational feature of the inner hexagon (Figure 16). The clinical abutment engages approximately 3.5 mm into the implant. The antirotational locking mechanism provides strength. The cylinders above and below the interhexagon feature provide stability. Placing the Frialit-2 silicone ring at clinical delivery will dramatically reduce microbiological leakage by providing a hermetic seal between the implant and the abutment. The laboratory will receive the ring with the purchase of the implant abutment and send it on to the dentist with the completed case.

One primary consideration for the dental laboratory in creating an ideal emergence profile through abutment selection is the depth of the soft tissue. The abutment selection also depends on whether the site is straight or angled, zero degrees or 14 degrees, and the thickness and depth of the tissue. Collar heights are available in 1-2 mm, 3 mm, and 5 mm (Figure 17). In this case, the depth from the top of the implant to the crest of the soft tissue on both the lingual and buccal is of concern. The abutment selected for this site is an MH-6 straight abutment, which has a 1-mm transmucosal extension. From the buccal view, the collar of the abutment is in an adequate position to be trimmed shorter. However, viewed from the lingual, it is a little too subgingival to aid the dentist in seating the crown. From the buccal view, the margin has been trimmed to within 7?10 of a millimeter from the top of the implant itself (Figure 18). This modification allows for a great emergence profile around the buccal and mesial and brings the margin lingually to the desired visual position. In this way, the clinician can visually approve the seat of the crown.

Selection and modification of the MH-6 abutments place the buccal margins in ideal positions. Only slight modifications to the anterior three implants were necessary; a more aggressive modification to the most posterior molar abutment was performed. Most of the abutment preparations are accomplished with a disc, a bur, or a rubber wheel.

Crown Fabrication

With the soft tissue removed from the master cast, the margins of each of the abutments and the abutment seat on top of the implant can easily be identified. Now, the occlusal and lingual screw holes are blocked out. After slightly lubricating the MH-6 abutment, an autopolymerizing castable resin is applied, accurately incorporating any modified margin. The autopolymerizing resin selected in this case was GC Pattern Resinu,c This resin is very fine grained and produces minimal distortion during setting. When set, the coping is thinned to a uniform, 0.5-mm thickness. This controls the expansion and contraction of the coping in the investment during the initial set and in the casting procedure. The coping is waxed to provide adequate strength of porcelain coverage, then sprewed, invested, and cast. The casting is divested and seated to the abutment.

The last step involves applying porcelain, glaze, and polish. Because we have fabricated the casting on the clinical abutment, the abutment and crown can be polished together, providing smooth transition from abutment to crown (Figure 19).

One of the strengths of the Frialit-2 Dental Implant System is the ability to achieve multiple single-tooth implant crowns in adjacent sites. With proper design and contour, these teeth can have an ideal emergence profile, and it is easy for the patient to access the area during oral hygiene procedures.

Delivery Considerations

To gain retention with the cement-on crown, the dentist applies a thin amount of cement around the marginal edge inside the crown. Because of the adequate fit of the crown casting against the modified abutment, the crown will be very stable.

In implant dentistry, the relationship between the implant surgeon, the restoring dentist, and the laboratory is paramount to success. With proper diagnosis and treatment planning using the Frialit-2 system, the dentist can easily achieve optimal function and esthetics by using the one impression coping to capture the position of the implant for the master cast. The dentist does not need to maintain an inventory of parts. The laboratory merely modifies the margin and fabricates the crown using conventional laboratory techniques. On delivery, the dentist simply torques in the abutment screw and cements the crown (Figure 20).

Prosthetic Delivery

First, the gingival formers are removed with the 0.09-hex driver. The silicon seals have been placed onto the abutment, and the prepared abutments are placed into the implant, engaging the hex to match their position from the master cast. Because multiple abutments were planned in this case, the laboratory placed corresponding numbers on the facial aspect of each abutment to match the number placed on the master cast. This eliminates any confusion when seating multiple abutments.

Before cementation, the abutment screws are threaded into position, all crowns are tried in, and minor adjustments to contacts and occlusion are completed. The abutment screws are torqued into position using 20-nc of force. The crowns are cemented using temporary cement, and lateral excursive contacts are eliminated. The occlusal scheme should be relatively flat, at no greater than a rational occlusal table.

Figure 21 illustrates the final radiograph of four single-unit implant crowns. Figures 22 and 23 illustrate the final esthetic result and emergence profile. Hygiene is made simple with normal flossing between the teeth (Figure 24).

All Frialit-2 abutments offer the opportunity to use either a cement-on crown or a screw-retained crown with a lingual fixation screw. The screws are precut, and the abutments are pretapped to allow for a screw-retained crown.

Conclusion

The Frialit-2 Dental Implant System allows for surgical predictability, reliable osseointegration, simple prosthetic techniques, easy laboratory control, and prosthetic stability. Smile design and emergence profile are the cosmetic principles in dentistry today. The variable diameters available with the Frialit-2 implant and selection of the appropriate abutments provide optimum esthetics. Single-tooth replacement of sequentially missing teeth has become the standard in modern implantology.

References

1. 7th International Friatec Symposium. Int J Oral Maxillofac Implants 12(4):697-702, 1997.

2. Wijs F, et al: Immediate labial contour restoration for improved esthetics: a radiographic study on bone splitting in anterior single tooth replacement. Int J Oral Maxillofac Implants 12(5): 686-696, 1997.

This issue of Perspectives in Implant Dentistry has been made possible through an educational grant from Friatec Dental USA. The opinions expressed herein are those of the author(s) and do not necessarily reflect those of the editorial staff or the publisher.

The views and opinions expressed in the article appearing in this publication are those of the author(s) and do not necessarily reflect the views or opinions of the editors, the editorial board, or the publisher. As a matter of policy, the editors, the editorial board, and the publisher do not endorse any products, medical techniques, or diagnoses, and publication of any material in this journal should not be construed as such an endorsement.

WARNING: Reading an article in Perspectives® does not necessarily qualify you to integrate new techniques or procedures into your practice. Dental Learning Systems expects its readers to rely on their judgment regarding their clinical expertise and recommends further education when necessary before trying to implement any new procedure.