INTRODUCTION
In all the years since 1963, when Dr. Per-Ingvar Brånemark invented the first titanium dental implant, much has changed in the implant world. Many of these changes have been for the better, resulting in more successful patient outcomes while providing greater clinical efficiencies.
Considering implantology’s relatively short history and rapid pace of advancement, a small group of clinicians, including the authors, conceived of a project to research the most beneficial implant products and procedures for practitioners to help them stay ahead of the implant technology curve. With this goal in mind, our group of 12 clinicians, representing multiple-doctor practices across the United States, met with implant engineers and manufacturers from around the world to research and discuss emerging trends. What we learned vastly changed all of our practices for the better, and now we will share the knowledge and perspective we gained with you.
This article represents the first installment in a series of planned articles. In each one, we will outline and explain, using abridged case studies, what our research has uncovered. An explanation of clinical applications and study findings enhance the takeaways gleaned from our implantology research.
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Bone Condensation, Densification, and Ridge Expansion
Perhaps one of the most influential trends observed concerns the topic of bone condensation, densification, and ridge expansion. At the Brånemarkonian starting point, the protocol provided for an osteotomy that was nearly the same diameter as the fixture, with a recommended insertion torque of less than 30 Ncms upon implant insertion. This protocol provided very little densification of the bone and relatively lower stability values. As a result, it produced what some clinicians call a “spinner,” where the threading had stripped within the osteotomy.
Over the last 20 years, recommended torque values have increased, stability has increased, bone densification has increased, and both immediate and slightly delayed loading have become the standard. Today, clinicians use a variety of auxiliary tools to influence the bone, from osteotomes to bone condensers to special drills functioning in reverse. In addition, the implant body design itself has evolved, allowing greater efficiency and simplicity for placement by clinicians and, ultimately, better patient outcomes with increased stability.
From Pilot to Final Drill: Simplified Drilling Protocols
Osteotomy preparation, which ultimately creates stability for implant placement, has traditionally been a time-intensive procedure for clinicians, limiting the number of implant placements that can be done in any given time period. However, efficiency in procedures has been improving.
Recent research1 that compares the traditional multiple-drill sequence to a simplified drilling protocol (pilot to final drill) found no difference in relation to success and osseointegration. The significance of this is that a simplified drilling procedure was comparable in overall implant success and patient outcome to the conventional drilling sequence, strongly suggesting that osteotomy preparation may be simplified. For clinicians on the cutting edge of efficiency, this news is a welcome advancement.
Such efficiencies open up numerous opportunities for clinicians. One such opportunity is to be able to utilize a self-drilling implant system without replacing an existing surgical drilling kit. Because much of the work is performed by the implant itself, often only requiring drilling down 75% of the osteotomy site, these modern implant systems will accommodate utilization of a wide variety of drilling systems. Because these osseocondensing, self-tapping, and self-drilling types of implants can be integrated directly into the existing suite of implant systems without having to purchase yet another surgical implant drilling kit, clinicians realize savings in both time and money. Additionally, this 100% compatibility feature allows clinicians to add advanced implant systems to their arsenals of tools and techniques without the high cost and redundancy of adding a new surgical drilling kit (Figure 1).
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Simplification of the Internal Sinus Bump
A simplified drilling protocol, combined with self-drilling aspects in the implant body itself, also allows for simplified and efficient treatment in the area of the sinus. Today, many cases that have sufficient bone inferior to the sinus can be successfully treated through bone condensation, self-drilling, and the creation of bone density. These techniques are very popular in Europe as a result of their minimally invasive attributes.
With the advent of short implants and the proliferation of research articles demonstrating the success rate of short implants, over time, the need for more extensive grafting procedures has been reduced. In areas with 6.0 mm or more of maxillary bone height, the clinician is able to provide a minimally invasive sinus bump and achieve bicortical stabilization. Sinus-friendly implants are often designed with a rounded end to safely provide this procedure. A slight taper also protects the implant from being lodged apically into the sinus. Figure 2 is a rendering of the physiological effect of a simplified drilling protocol coupled with under-drilling the osteotomy. Fewer drills and under-drilling (both in diameter and length) help to achieve greater primary stability levels and increase the density of bone cells around the implant, thus creating osseocompatibility.
A recent study2 provides fabulous insight into the benefits and limitations of osteotomy and lateral antrostomy. For instance, when less sinus augmentation is required, the osteotomy (indirect) technique is often suitable. For cases with more advanced resorption, a lateral antrostomy can create sufficient bone height for optimal implant-length placement. Both sinus elevation techniques mentioned here result in excellent implant success rates. As a result, clinicians can employ minimally invasive sinus bump procedures without the need for a relatively invasive surgery—again creating greater efficiency in the clinical setting.
Shifting from procedural efficiency to advancements in implant fixture design, we see that many modern systems offer safety features in relation to sinus areas. Here are beneficial implant design attributes to consider that help to successfully provide outcomes and efficiencies as illustrated:
- A taper, helping to prevent over-insertion toward the sinus cavity
- The transfer/abutment being attached to the implant, allowing for more control
- A rounded apex, to help push/reflect the sinus floor without damage
There is much less technique sensitivity to the closed technique. A comprehensive study3 of implants placed in very atrophic maxillary ridges with an average of 3.8 mm of residual height without grafting material helps broaden treatment options for this all-too-common occurrence. In this study, tapered implants were placed in maxillary sites with a residual bone height of 1.0 to 6.0 mm using a technique without grafting material that resulted in high success rates. As a result, it is possible to achieve implant primary stability in poor-density bone, even with an available bone height of under 6.0 mm, with implants that feature osteotome-like physical properties (Figure 2).
The conclusion that most similar studies suggest is that if vertical bone augmentation of 5.0 mm or less is needed, then the internal lift may be preferred. The main advantage of this technique is a reduction in operating time. When more than 5.0 mm of bone growth is needed, the lateral wall may be the better procedure choice. This procedure offers enhanced visualization of the membrane to observe and fix perforations and the potential to add more bone volume predictably.
It is important to note that recent studies4 show that the placement of short implants (6.0 mm minimum) entirely in native bone is preferable to sinus floor elevation with the simultaneous placement of standard (> 8.0 mm) implants due to a lower incidence of complications and similarly high survival rates. For this reason, it is perhaps most advantageous to clinicians to familiarize themselves with short, wide implants per the illustration in Figure 2. The clinician should assess the viability of performing a procedure similar to that in Figure 2 to create the least invasive option.
Conversely, Figure 3 shows an example of a case with atrophic and minimal ridge height and width requiring a ridge splitting with grafting procedure.
In this particular case, if there was a narrow ridge with plenty of ridge height, then it would be prudent to use a narrow diameter implant. The illustration in Figure 4 demonstrates the advantage of modern implant engineering and its simplification, coupled with reduced invasiveness, in performing a narrow ridge procedure.
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Evolution of Single-Arch and Full-Arch Prosthetics
Early loading protocols are applicable for implants placed with a high degree of primary stability, as per the simplified drilling protocol illustration. (Figure 4). Keeping with our theme of efficiency and simplification is the now established procedure of the “all on X” immediately loaded screw-retained temporary restoration shown in Figure 5 using the more aggressive tapered implants.
Much has changed in the arena of full-arch prosthetic solutions. Years ago, the standard was a full-arch titanium or chromium-cobalt frame with pink acrylic and denture teeth (hybrid denture). Since then, the standard has evolved as deficiencies with pink acrylic and denture teeth with a metal framework have evolved to include premature wear, greater vertical dimension needed, reduced precision, and breakage of both denture teeth and acrylic. As the accuracy and precision of zirconia milling has improved, major strides have been made in the design of full-arch prosthetic solutions. Additionally, the aesthetic treatment of the zirconia base with staining or layered porcelain has created superior aesthetics unrivaled by outdated hybrid dentures. Dr. Michael Tischler has been responsible for many of the innovations related to the full-arch zirconia revolution. The evolved full-arch zirconia bridge, coupled with the surgical and implant advances previously mentioned, creates the best dentistry has to offer for both the patient and clinician.
CLOSING COMMENTS
Advancements in implant design and techniques continue to emerge from research, manufacturing and design advancements, and clinical practices worldwide. The case examples illustrated in this article demonstrate just a few of these developments and the benefits they offer both clinicians and patients. As digital workflows, manufacturer innovations, and procedural developments continue to unfold, clinicians will be able to more effectively and efficiently address patient needs through implantology.
Be on the lookout for the next installment in this article series in Dentistry Today, as we explore minimally invasive extraction techniques and subsequent immediate implant placement with some modified efficiency protocols. One featured case study will involve 3-D printing a full-arch temporary in preparation for the final full-arch zirconia restoration prior to full-arch extractions and grafting.
References
- Giro G, Tovar N, Marin C, et al. The effect of simplifying dental implant drilling sequence on osseointegration: an experimental study in dogs. Int J Biomater. 2013;2013:230310.
- Pal US, Sharma NK, Singh RK, et al. Direct vs. indirect sinus lift procedure: a comparison. Natl J Maxillofac Surg. 2012;3:31-37.
- Nedir R, Nurdin N, Szmukler-Moncler S, et al. Placement of tapered implants using an osteotome sinus floor elevation technique without bone grafting: 1-year results. Int J Oral Maxillofac Implants. 2009;24:727-733.
- Fan T, Li Y, Deng WW, et al. Short implants (5 to 8 mm) versus longer implants (>8 mm) with sinus lifting in atrophic posterior maxilla: a meta‐analysis of RCTs. Clin Implant Dent Relat Res. 2017;19:207-215.
Additional Reading
Klein MO, Schiegnitz E, Al-Nawas B. Systematic review on success of narrow-diameter dental implants. Int J Oral Maxillofac Implants. 2014;29(suppl):43-54.
Schimmel M, Srinivasan M, Herrmann FR, et al. Loading protocols for implant-supported overdentures in the edentulous jaw: a systematic review and meta-analysis. Int J Oral Maxillofac Implants. 2014;29(suppl):271-286.
Khayat PG, Arnal HM, Tourbah BI, et al. Clinical outcome of dental implants placed with high insertion torques (up to 176 Ncm). Clin Implant Dent Relat Res. 2013;15:227-233.
Dr. Williams received his DDS degree from the Texas A&M University System Health Science Center Baylor College of Dentistry. He is in private practice with his brother in Allen, Texas. He is an alumnus of the renowned Las Vegas Institute for Advanced Dental Studies and an associate Fellow in the American Academy of Implant Dentistry (AAID). He can be reached at drstevew100@gmail.com.
Dr. Ammons graduated magna cum laude from Clemson University with a bachelor’s degree in chemical engineering. He earned his DMD degree at the Medical University of South Carolina School of Dental Medicine. After graduation, he completed an Advanced Education in General Dentistry residency at the Charlie Norwood VA Medical Center in Augusta, Ga, where he focused on surgical placement and restoration of dental implants. Prior to opening his current practice, Dental by Design, Dr. Ammons was the owner and operator of a traveling dental implant service in the Charleston, SC area. He can be reached at mwammons@gmail.com.
Dr. Bessonet received his bachelor’s degree from Louisiana State University (LSU) in 1998 and went on to earn his DDS degree from the LSU School of Dentistry in 2003. He is currently the chief faculty member of the Louisiana Implant Institute. Dr. Bessonet is a member of the ADA, the AAID, the American Dental Society of Anesthesiology, and the International Congress of Oral Implantologists (ICOI). He has also achieved Fellowship in the AGD. He can be reached at ascensiondentist@eatel.net.
Dr. Dostal, of the KC Implant Institute, completed his undergraduate studies at the University of Kansas and completed his dental degree at the University of Missouri, Kansas City. He is recognized as an expert in comprehensive restorative treatment using implants, full-arch implants, full-mouth reconstruction, and orthodontics. He is a member of the ADA, the Kansas Dental Association, the International Association for Orthodontics, and the AAID and a Fellow of the ICOI. He can be reached at dostalmike@gmail.com.
Disclosures: The authors have a financial interest in some of the products mentioned in this article but received no compensation for writing it. All authors are paid faculty members for IH Biomedical.
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