Innovations in Implantology
Advances in surfaces, perio-prosthetic platforms, digital workflow, and materials from the single molar to the full arch
Bobby Birdi, DMD, MSc | Angus Barrie, RDT | Felipe Ouriques, DDS, MSc | Catherine Chay, CDA
Dental implantology is an ever-growing and progressing field. In the mid to late 1900s, early implant dentistry was conservative in nature and involved long healing times, conventional impressions, implants with machined surfaces, and delayed loading. This was mainly due to high implant failure rates.1 Furthermore, planning was analog in nature, which somewhat hindered patient and interprofessional communication. However, since the 1990s, there has been great advancement in the field, including the incorporation of digital technology, immediate implant placement, developments in grafting, and immediate implant loading as well as the advent of computer-guided surgical methods using in-office cone-beam computed tomography (CBCT) technology. Dental implantology has come a long way in just over two decades, and it is continuing to evolve and offer new solutions.
Today, with the ability to digitally plan a case in all aspects, immediately place an implant using various forms of guided surgery, and immediately place a pre-milled provisional (and in some cases, a final restoration2) on the day of surgery for a single tooth or a full arch, one may question, "Where does implantology go from here?" Innovation is needed for any field to evolve; however, it is important to understand the basics and remember that innovative technology is not a replacement for the development of proper surgical technique and should only serve as a tool for clinicians to achieve more precise and ideal results on a routine basis in less time and with less invasiveness.
This article presents three cases that highlight the use of some new innovations in dental implantology that may help to further the progression of the field and lead to benefits for cases in the future.
Case 1: The Immediate Molar
A healthy, 45-year-old male patient was referred to our clinic because his maxillary left first molar (tooth No. 14) had fractured off at the gumline. This tooth had been previously undergone endodontic treatment, and the endodontist who referred the patient indicated that he had found a vertical root fracture in the tooth and thus deemed it to be hopeless. A CBCT scan and a periapical radiograph were acquired to evaluate the area (Figure 1). Buccal bone loss was evident as well as intimate involvement with the maxillary sinus. After discussing various options with the patient, he elected to have the tooth removed and replaced with a dental implant.
At the surgical appointment, the tooth was atraumatically extracted using a flapless approach, all of the granulation tissue was removed, and the socket was thoroughly flushed with a saline solution. A 5.5 mm x 13 mm implant (Nobel Parallel™ Conical Connection TiUltra™, Nobel Biocare) was placed 3 mm below the proposed final gingival zenith3 with a simultaneous indirect sinus lift (6 mm), whichwas performed using burs (Densah™, Versah) run in reverse (Figure 2). This implant length was required to engage the palatal socket bone and attain bicortical fixation. The sinus graft was completed with leukocyte- and platelet-rich fibrin (L-PRF) and a bovine-derived bone graft (Creos™ Xenogain, Nobel Biocare) congealed with platelet-rich plasma (PRP). The use of L-PRF/PRP facilitates the placement of autogenous platelets on the implant surface, which are the first cells needed in the process of osseointegration. Upon insertion, the implant demonstrated an initial stability of greater than 50 Ncm. Next, a perio-prosthetic platform (On1™ Base Xeal™ Conical Connection, Nobel Biocare) was placed into the implant, torqued to 35 Ncm (Figure 3), and covered by a PEEK healing cap (On1™ IOS healing Cap, Nobel Biocare), which would also double as a digital impression coping (Figure 4).
The implant-abutment connection is an important section of the dental implant complex to consider. It has been established that the tissues adhere to the components at this interface, and it has been shown that numerous disruptions (eg, swapping of components) to the implant-abutment connection can result in tissue damage, irritation, and subsequent bone loss.4-6 Conversely, a reduction in bone loss has been demonstrated when the final abutment is connected to the implant on the day of surgical placement and then never removed.4-6 The perio-prosthetic platform selected for this case was designed to seal off the implant-abutment connection on the day of surgery utilizing a surface coating that aids in tissue adherence.
After 12 weeks of healing, the integration of the implant was verified, and a digital impression (Trios 4™, 3Shape) was taken with the existing healing cap in place. Two weeks after that, the final screw-retained monolithic zirconia crown (IPS e.max® ZirCAD® Prime, Ivoclar Vivadent), which was fabricated in an in-house, full-service laboratory, was delivered and torqued to 35 Ncm. The patient was recalled a year later for a follow-up, and a periapical radiograph indicated the presence of ideal health and bone levels (Figure 5).
Immediate implant placement in molar sites can be challenging due to anatomical limitations, bone quantity, and the difficulty of achieving initial stability. Selecting an implant with a tapered apex, such as the one used in this case, can alleviate many of these challenges because they allow for the osteotomy to be undersized, which results in excellent initial stability. In addition, the selection of an appropriate implant width and an appropriate implant connection size that best relate to the dimensions of the tooth to be replaced is imperative to long-term success.7 In light of this, placing an implant with a diameter that is larger than 5 mm and a wide connection size is ideal for a molar site in terms of the forces involved and the required emergence profile.8
Case 2: The Immediate Anterior Bridge
A 32-year-old female patient presented to our clinic from overseas with both maxillary central incisors (teeth Nos. 8 and 9) demonstrating class 2 mobility. They were being used to cantilever pontics to replace her congenitally missing lateral incisors, and she wanted dental implants to replace them. A CBCT scan, periapical radiograph (Figure 6), and clinical photographs (Figure 7) were acquired to evaluate the area. Teeth Nos. 8 and 9 exhibited poor crown-root ratios and had poor prognoses. Digital impressions were also captured. A workup utilizing digital smile design (DTX Studio™, Nobel Biocare; Implant Studio, 3Shape) was completed in order to facilitate fabrication of a 3D printed surgical guide for immediate implant placement and provisionalization at site Nos. 8 and 9. These sites were selected because the congenital absence of the patient's maxillary lateral incisors had resulted in significant bone loss in the areas of site Nos. 7 and 10. The patient approved the smile design and consented to the treatment.
On the day of surgery, teeth Nos. 8 and 9 were removed atraumatically using a flapless approach, and implants with a novel surface coating (NobelActive® TiUltra™, Nobel Biocare) were placed into the sites, 3 mm below the gingival zeniths of the proposed final restorations, using a fully guided surgical protocol with a 3D printed surgical guide that was produced in-house (Figure 8 and Figure 9). Simultaneous osseous grafting was performed using L-PRF and a bovine-derived bone graft (Creos™ Xenogain, Nobel Biocare) congealed with PRP. Following implant placement, a final digital impression was acquired, and an immediate screw-retained provisional restoration was delivered out of occlusion (Figure 10). The patient then returned overseas.
Four and a half months after the surgery, the patient returned to the clinic. The final screw-retained zirconia prosthesis (IPS e.max® ZirCAD® Prime, Ivoclar Vivadent), which was fabricated in advance, was then delivered without any further impressions (Figure 11 and Figure 12). She was very pleased with the shape and esthetics of her final prosthesis and that she was able to replace her four maxillary incisors in just three appointments during two return visits while living overseas.
The use of software that permits the amalgamation of CBCT image data (ie, DICOM) and digital impression data (ie, STL) is crucial in the digital workflow. The digital workflow can then be realized by accurately planning the 3-dimensional position and mechanical facets of the final restoration to allow for ideal implant placement. The ability to digitally plan the final restorative contours with respect to the desired esthetic smile design is also an advantage of today's digital planning software. Once the projected implant position is planned, it is then transferred from the digital workflow to the patient through fully guided surgery using a 3D printed surgical guide.9
By properly planning the case in all restorative dimensions in advance, the surgery can be accurately completed to allow for the final digital impression on the same day, and thus, the fabrication of the final prosthesis without the need for another appointment. This approach should only be used when tissue/bone contours are ideal and will not need significant augmentation and in areas where the esthetics are not crucial (eg, molar areas). Furthermore, it is only when the final implant position is planned based on the ideal position, contours, and design of the final restoration, that the need for adjunctive procedures such as osseous or soft-tissue augmentation can be appropriately considered.
Case 3: The Immediate Full-Arch Prosthesis
An otherwise healthy 80-year-old male patient presented to our clinic with only four maxillary teeth remaining, which were fractured. His mandibular arch was also compromised, but he wanted to focus on treating his maxillary arch first. A CBCT scan (Figure 13) and clinical photographs (Figure 14) were taken to evaluate the area. His maxillary dentition was deemed hopeless, so he was provided with various options for full-arch replacement. To replace his maxillary dentition, he chose a zirconia hybrid prothesis that would be supported by 4 to 6 implants. After digital impressions and photographs were acquired and an assessment of the smile line was completed, a milled poly(methyl methacrylate) (PMMA) immediate maxillary denture was fabricated (Ivotion Denture System, Ivoclar Vivadent) to be converted on the day of surgery. It should be noted that digital impressioning of edentulous areas can be challenging because intraoral scanners record the soft tissues differently than teeth. Furthermore, tissue consistency and compressibility can also be difficult to interpret digitally without a proper technique. Milled PMMA has been shown to be stronger, less porous, and more durable than conventional acrylic.10 The denture setup was digitally designed to be ideal, and then the minimum amount of bone reduction needed to hide the transition line and provide enough restorative space for the final restoration was calculated along the arch.
When the patient returned for surgery, his maxillary teeth were removed atraumatically using a flapless approach. The immediate denture was then placed, and the vertical dimension, esthetics, and phonetics were verified prior to proceeding any further with the surgery. Next, a conservative flap was reflected, and precise, minimal bone reduction was completed based on the digital plan. Five implants (Nobel Parallel™ Conical Connection TiUltra™, Nobel Biocare) were then placed, each of which was torqued to an initial stability of greater than 50 Ncm (Figure 15). These implants were placed anterior to the maxillary sinuses using an angled placement protocol and bicortical fixation. Following implant placement, angled multi-unit abutments with a surface coating designed to promote mucointegration (Xeal™, Nobel Biocare) were connected and torqued to the manufacturer's specifications (Figure 16). The denture was then converted into a provisional full-arch fixed hybrid prosthesis and delivered (Figure 17). The patient was placed on a soft diet for 8 weeks.
At the 16-week mark, the patient returned to the clinic, integration was verified for all of the implants placed, and the final monolithic zirconia hybrid prosthesis (IPS e.max® ZirCAD® Prime, Ivoclar Vivadent) was delivered. The patient selected a monolithic zirconia prosthesis to eliminate the possibility of any porcelain chipping; however, he still achieved a highly esthetic result because the material was a blend of both 5Y and 3Y zirconia (Figure 18).
During the last 10 to 15 years, full-arch implant therapy has become more popular, and the use of digital technology and proper planning can facilitate routinely predictable results. The use of stackable guides to provide this type of therapy is also a great option, but it can add significant costs to the treatment and often results in larger, more invasive flap designs. Incorporating innovative materials may also decrease the chance of prosthetic complications in the future, such as the chipping of prostheses.
Conclusion
These cases illustrate the need for proper planning in all implant cases, including the importance of planning the final restorative design prior to the initiation of any surgical therapy. Digital technology makes this much easier to achieve, and the use of promising innovative materials may reduce the risk of restorative complications.
In all three of the cases documented, the use of components with innovative surfaces, including implants, a perio-prosthetic platform, and abutments, may have provided benefits regarding bone retention as well as tissue stability and health. Furthermore, the gold color of the various anodized surfaces may aid in preventing any greyness from being seen through the tissues, even when issues arise,11 and these surfaces may be more biocompatible with the soft tissues, which could offer a very large long-term advantage.
About the Author
Bobby Birdi, DMD, MSc
Private Practice
Vancouver, British Columbia, Canada
Angus Barrie, RDT
Chair, Board of Directors
College of Dental Technicians of British Columbia
Richmond, British Columbia, Canada
Felipe Ouriques,
DDS, MSc
Private Practice
Florianópolis, Santa Catarina, Brazil
Catherine Chay, CDA
Private Practice
Vancouver, British Columbia, Canada
References
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