Introduction
Osteointegration, as described by the founding fathers of modern implantology in the 1980s, involves a direct and functional connection between the surface of an implant and the living bone. Since the 1980s, two models have been developed. "Bone Level" implants, with external connection and a smooth surface, are intended to be placed in two surgical steps and result from the work of P.I. Brånemark; "Tissue Level" implants, developed by Schröeder's team, have a rough surface and are placed in one surgical step.
The formation and maintenance of this osteointegration are crucial to the survival of the implant. Thirty years later, driven by the first results obtained, the success of these implants is defined by ever more precise criteria, from marginal bone loss to the perfect aesthetic integration of the prosthesis.
These requirements of patients and practitioners translate to a healthy daily race forward for research and industry to obtain ever more reliable medical instruments and devices. Technological advances in materials science, nanotechnology, mechanics and biomechanics, as well as advances in our understanding of biological phenomena, have made it possible in recent years to market dental implants that provide an ever-expanding range of options for the treatment of our patients.
However, today, the success and even the survival of our implants, though previously taken for granted, seem to be called into question by the rise of peri-implantitis.
While the scientific community unanimously agrees on the good long-term performance of "Tissue Level" implants with rough surfaces as defined in Schröeder's original work, there has been an increase in the number of case reports involving peri-implant complications related to the combination of "Bone Level" implants and rough surfaces. This combination is far from the original work of Brånemark, which advocated for the use of a smooth surface with this type of implant (or at least for implants with an external connection).
However, "Bone Level" implants are fully justified in all cases with an aesthetic impact, in patients with fine biotypes, and in the maximum use of residual bone in the perisinus region, for example. Finally, a return to a smooth surface would constitute a significant step backwards in terms of operating protocols, particularly in all cases of immediate implant placement in fresh extraction sockets, immediate loading, or when a bone regeneration technique is to be applied simultaneously with the implant placement.
The nature of the connection and the way in which the biological space is established therefore seem to be decisive factors in protecting the rough implant surface from such complications.
The gold standard of the "Bone Level" implant can today be defined as an implant which, when placed in accordance with the data acquired from science, allows for optimal respect of the biological space thanks to its neck and connection. The connection of the prosthetic elements is moved towards the center of the platform: this "platform switching" combined with a sealed Morse taper connection makes it possible to limit the inflammatory zone of the microgap and move it away from the bone.
Around this connection is a smooth surface that is directly exposed to the soft tissue to form the horizontal component of the biological space, and a rough osteoconductive surface that is placed in contact with the bone along the implant. The biomechanical characteristics of the design of the body and apex of the implant must allow for significant primary anchorage, and dynamic bone management in the different density types, as well as optimal evacuation of the stress induced by this design intended to increase the stability of the implant, particularly in cortical areas, which are extremely sensitive to resorption phenomena.
For the "BLX" implant, significant progress has mainly been made in relation to these three points. The advantages of improved primary stability are not only limited to the aesthetic or immediate loading possibilities. In all indications, from the most extreme to the most common, a direct correlation between initial implant stability and the phenomenon of osteointegration has been demonstrated. This is especially true for all low bone density sites — posterior sub-sinusal maxillary areas, grafted or regenerated sites, on the day of extraction or after mucosal healing, in the maxilla or mandible.
The Evolution of Implant Designs
In this biomechanical research on increased primary stability, several designs have been proposed:
- A parallel-pitch design, naturally coupled with simple and efficient drilling that has the advantage of being flexible in terms of vertical positioning, but does not allow significant primary stability to be achieved in low-density bones and extraction cavities.
- A completely tapered design, the drilling of which is much more demanding and where the positioning of the implant does not allow for any errors. The number of drills required is much higher since one drill is required for each implant length and diameter.
- A hybrid design, parallel on the coronal portion and tapered on the last 5 mm of the apex. This combination benefits from the flexibility of parallel-pitch implants and the increased primary stability of tapered designs — particularly useful when one wall of the implant bed is deficient.
- More recently, a conical design with aggressive self-drilling threads has emerged, quickly gaining favor for immediate implant placement in extraction sockets. However, these implants have not proven effective in D1 or D4 bones.
The "BLX" implant represents the latest generation of self-drilling implants. The main progress made has been in dynamic bone management and the limitation of stress in the implant's direct environment — allowing greater flexibility for the user while preserving the ability to obtain predictable primary anchorage, even when bone quality varies.
The BLX Implant in Detail
Apical portion
The first characteristic of this self-drilling implant is its rounded and softened apex, which provides better protection against anatomical obstacles: mandibular nerve, maxillary sinus, or converging dental roots. To allow the implant to engage the surrounding bone tissue, the end of the implant is quickly surrounded by wide threads which also enable the operator to control the direction of insertion during implant placement.
Design of implant threads
The BLX implant features double threads whose spacing and width vary according to their position on the implant, and also according to the implant length. This unique design allows for efficient and fast insertion, ideal primary stability in all types of bone through uniform and controlled compaction and densification of peri-implant bone, and optimized insertion torque values guaranteeing maximum dissipation of stress.
Core portion
The BLX implant has a narrow conical central portion: ø 3.5 mm for RB implants and ø 4.5 mm for WB implants. This narrow implant body, coupled with the progressive thread design, limits insertion constraints and stress delivered to the surrounding bone tissue, even in the case of a relatively small osteotomy.
Cutting capacity of the threads
The secant threads give the BLX implant its unique capabilities. Sharp in both directions, they allow for significant relaxation of the insertion torque when the implant is unscrewed — eliminating the need for a tap. The implant itself acts as the last instrument in the operating sequence.
Full-length chip flute
Present along the entire length of the implant, these lateral grooves give it its unique ability to collect the bone chips cut by the implant threads. These grooves allow the bone collected around the implant to be evenly redistributed to build a reinforced interface using the compaction capabilities of the implant. This configuration results in optimal bone-to-implant contact all around the implant.
Implant neck of reduced diameter
The reduced diameter of the implant neck minimizes the stress on the cortical bone at the end of insertion. The bone cortex therefore does not need to be adjusted by an additional surgical instrument and bone resorption is limited to a minimum during the remodeling phase following insertion of the implant, allowing for optimal maintenance of the crestal bone.
TorcFit® connection
The BLX implant has a single connection regardless of implant diameter. In addition to reducing the surgical and prosthetic components required to use this implant and thus considerably simplifying the daily management of the various instruments, this connection with improved mechanical properties allows prosthetic parts of reduced diameter to be used to draw maximum benefit from the platform switching phenomenon by increasing the volume of soft tissue around the implant neck. In addition, the use of these narrower parts considerably reduces the risk of bone interference when inserting various prosthetic components.
Roxolid® and SLActive® surface
Finally, the BLX implant is only available with the combination of Roxolid® alloy and SLActive® surface. This allows it to be approved for all indications from 3.75 mm diameter onwards due to the elevated mechanical properties of the Roxolid® alloy. In addition, the excellent behavior of the SLActive® surface allows for shorter osteointegration times, better results in immediate loading protocols, better healing of peri-implant defects in cases of immediate implant placement, and better behavior in specific circumstances (smokers, diabetics, etc.).
Surgical Protocol
The BLX surgical protocol is simplified and adapted to bone density, with the implant acting as the final instrument of the sequence:
| Step | Soft bone | Medium bone | Hard bone |
|---|---|---|---|
| Mark site | Needle Drill ø 1.6 mm | ||
| Pilot drilling | Pilot Drill ø 2.2 mm → Alignment Pin | ||
| Finalize bed | Drill 3 (ø 3.2) | Drill 3 · Drill 6 (ø 4.2) · Drill 7 (ø 4.5) | Drill 3 · Drill 6 · Drill 8 (ø 5.2) |
| Placement | BLX implant insertion | ||
Clinical Situations
The management of narrow spaces due to converging roots
The pre-implant analysis systematically includes radiographic analysis. The presence of converging roots is detectable on peri-apical X-rays and CT scan. The bone volume available for implantation is sometimes reduced by adjacent converging roots; damage to the cementum or dentin caused by drilling can trigger external resorption, fracture, or even necrosis. When the residual volume is too small to guarantee a safe distance from anatomical obstacles, it is a local contraindication and pre-implant orthodontic treatment is necessary. In less clear-cut situations, the use of an implant with apical conicity — such as the BLX — saves space and allows placement in the desired position while avoiding adjacent roots.
Immediate implant placement in the posterior area
Since an early publication in 1989, immediate implant placement after single-rooted tooth extraction has become a regularly proposed procedure, since successfully extended to multirooted teeth. Cumulative survival rates for implants placed immediately after molar extraction are comparable to those placed in healed sites. The essential factor for success is initial implant stability via apical and/or lateral bone. At a molar extraction site, primary stability may be difficult to achieve due to socket size, poor bone quality, or anatomical limitations (maxillary sinus, mandibular canal). The specific design of the BLX allows satisfactory primary stability even in a very reduced septum.
Immediate treatment of a lateral sector
In cases of multiple missing teeth, temporization management can be challenging. When sufficient primary stability is achieved, immediate loading is possible. The use of SRA (Screw Retained Abutment) on Bone Level implants compensates for axis deviations while maintaining a sealed connection at bone level. A temporary bridge can be fabricated in the same surgical session, allowing fixed implant-supported temporization.
Immediate implant placement in a mandibular canine site
Immediate implant placement with provisionalization also allows the pre-existing tissue architecture (gingival contour and interdental papillae) to be maintained. The following case presents a lower right canine deemed hopeless following an iatrogenic germectomy. An extraction-implantation procedure with immediate provisionalization was performed to preserve the soft tissue architecture.
Immediate implant in a central incisor site — chairside temporary crown
The immediate implant-supported temporary crown is of paramount importance for healing and shaping surrounding tissues. In immediate placement cases, placing the implant through a guide with a fully pre-fabricated crown is rarely satisfactory due to palatal cortex constraints. Mastering a simple chairside protocol — bonding a temporary abutment to a digitally designed hollow crown — allows fabrication of a temporary crown in minutes, with an emergence profile that is concave buccally and straight or slightly convex proximally.
Immediate implant placement in a maxillary canine site
Gap management between the implant and cortical bone during immediate implant procedures is one of the most debated topics in implantology. Solutions include xenograft filling using the "dual zone" technique, partial root extraction (shield technique), or connective tissue graft. To recreate essential gingival volume in the canine area and compensate for slight loss of vestibular cortex integrity, a connective tissue graft was combined with immediate implant placement. The graft was harvested from the tuberosity, offering very dense connective tissue that remains stable over time.
The concept of strategic extractions
The transition to complete or widespread edentulism often makes surgical guide stabilization challenging. Tooth-supported guides (merged digital model + CT scan data) are more reliable than bone- or mucosal-supported guides. When a patient retains multiple unsalvageable teeth, precise planning can identify "strategic" teeth not located at implant sites, which are kept in place solely to stabilize the surgical guide — allowing tooth-supported guided surgery of high precision.
Treatment of a maxillary full arch with immediate loaded implants
Healing of Bone Level implants under a complete removable denture can lead to bone resorption, cover screw exposure, or implant failure. Immediate loading, in addition to patient comfort, makes the treatment more reliable. Success depends on sufficient primary stability and an accurate protocol for impression-taking and fabrication of the immediate temporary bridge.
In this case, two distal implants were angulated along the anterior sinus wall to avoid a sinus lift procedure. SRA abutments were used to correct axial discrepancies while maintaining a sealed connection at bone level. A customized impression tray (duplicate of the complete denture) was hollowed out at implant sites to register implant positions with plaster.
