INTRODUCTION
Implant dentistry has come a long way in helping the general dentist plan and treat the concerns and needs of edentulous patients. Each patient has unique situations that need to be thoroughly evaluated, and, therefore, case-appropriate diagnoses and treatment plans are imperative to realize successful outcomes of care. Anatomic limitations should be addressed, as well as surgical considerations and the final prosthetic design. Soft-tissue anatomy and implant osseointegration must be understood prior to any surgical intervention, and the clinician must visualize the outcome of a case before beginning it. If there are contraindications or conditions known to complicate treatment, pursuing the implant option may lead to further complications and/or surgical failure. For example, attempting to maintain teeth with a poor long-term prognosis is not in the best interest of the patient.
There are several criteria for patients for whom the clinician is considering dental implants as a treatment option. The patient should be in good overall health with no known healing problems, including uncontrolled diabetes, uncontrolled hypertension, or immunosuppressive diseases, among other conditions. Smoking can also prohibit proper blood supply to the surgical site. There must also be adequate bone quantity and quality to further support the implant and its foundation. Herein, we will describe a predictable protocol for bone regeneration. The position of the mucogingival line should be evaluated prior to implant placement. There needs to be a band of at least 2.0 mm on the facial aspect of all our implants. This attached gingiva provides protection and external barriers to potential external injury and is critical to proper tissue healing around the dental implant. Attached gingiva is also important to prevent food impaction and postoperative tissue shrinkage. Furthermore, without proper attached gingiva, plaque accumulation may compromise the site.1
Patients present to our office after gathering information about their dental conditions from the internet or other practitioners. Dental implants certainly have become a topic of interest. Options for the patient, concerning his or her condition, need to be carefully planned and explained. Visual images provided by CBCT help the practitioner explain these options and potential treatments. CBCT evaluation is a tool that has made the practicing dental implant surgeon better prepared to evaluate potential implant sites. Diagnosing and treatment planning are made more efficient as 3 dimensions can be evaluated. CBCT scanners are pieces of equipment that the implant dentist should embrace. A preoperative CBCT scan, using the PaX-i3D Green imaging system (Vatech America), shows the axial, sagittal, and coronal planes. The axial plane is the plane parallel to the ground, thus dividing the face from top to bottom. The sagittal plane is perpendicular to the ground, dividing the face from right to left, and is most useful to evaluate the amount of available bone height and width from facial to palatal. Finally, the coronal plane is perpendicular to the ground and divides the face from front to back.
A “tooth-down” approach is the most efficient method to idealize the final outcome. Designing the emergence profile and smile design can be completed pre-op. Knowing where the final restoration needs to be will allow for idealization of the implant placement, eliminating errors in positioning and function. Vital anatomy can be evaluated and addressed. Damaging vital structures can result in significant trauma.2 Immediate placement of a dental implant can be done as long as infected tissue is thoroughly curetted and the implant can maintain initial stability and torque.3
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CASE REPORT
A 67-year-old male presented with discomfort in and around tooth No. 24. The patient had no contraindications involving his overall health and was solely on 81 mg of Aspirin for prophylactic coverage.
Endodontic therapy had been previously scheduled with an endodontist as well as a follow-up restorative appointment with his current GP dentist. After hearing about and supporting these initially presented treatments as viable options, an alternative plan to remove the natural tooth and provide a same-day option of an immediately placed dental implant was presented. The patient elected to move forward with our treatment plan.
The pre-op facial view of the patient showed an active fistula between the mandibular central incisors (Figure 1). The conventional 2-D digital radiograph appeared to indicate an abscess had formed in the mandibular incisor (Figure 2). Root canal therapy was presented as an option. However, the sagittal view of our Green CT (Vatech America) analysis (Figure 3) indicated significant facial bone plate loss. The long-term prognosis following endodontic therapy would likely be poor in this circumstance. It was decided with the patient that an appropriate treatment plan included removal of the tooth, immediate implant placement, and grafting of the site to reform the facial plate.
Figures 4 and 5 illustrate how the infected tooth was carefully removed and the socket site thoroughly curetted to remove all granulation tissue from the surgical area. The missing facial bone was evaluated using a periodontal probe (Figure 6). The attached gingiva was reflected and the significant bone loss evaluated (Figure 7). The granulation tissue was removed, and a Straumann Bone Level Tapered (BLT) Implant depth gauge was passively placed into the socket to determine angulation and depth prior to any widening or lengthening of the osteotomy (Figures 8 and 9). The Straumann BLT Implant surgical protocol was followed in this case. Figures 10 and 11 illustrate the use of a pilot bur to idealize mesial-distal angulation and depth. The osteotomy was widened (Figures 12 and 13). The Straumann BLT Implant was then threaded into the osteotomy site at a slow speed (25 rpm). Next, the implant was strategically positioned approximately 1.0 mm subcrestal to account for potential physiologic bone shrinkage as integration progressed after tooth extraction (Figures 14 and 15). The post-op periapical radiograph (Figure 16) indicated the position of the implant was at 1.0 mm subcrestal. A resorbable membrane (Straumann) was then cut and shaped to fit the defective site, and the membrane was placed to extend at least 2.0 mm apical and mesial and distal to the defective site. Next, the membrane was passively tucked over the implant and under the lingual tissue (Figure 17). Allograft material (Straumann) was wetted with sterile saline and carefully positioned and then covered with the resorbable membrane (Figure 18). The reflected tissue was repositioned and sutured to place (Vicryl sutures) (Figure 19). The natural tooth that had been extracted was then bonded to the adjacent tooth to serve as a provisional as integration progressed (Figures 20 and 21). The final periapical radiograph was then taken (Figure 22).
Following integration of the implant, the attached gingiva was evaluated (Figure 23). The implant was ready to be uncovered for an impression. A confirmation radiograph was made at the uncovering appointment (Figure 24). The Straumann BLT impression coping was then inserted into the implant, and a vinyl polysiloxane impression (Panasil [Kettenbach LP]) was taken (Figures 25 and 26). The post-op CBCT analysis indicated bone growth onto the facial aspect of the dental implant (Figure 27). The dental laboratory team fabricated a custom titanium abutment that was torqued into position (Figure 28). The access hole of the abutment was covered with a cotton pellet and then Cavit (3M) (Figure 29). Figure 30 illustrates the final implant-retained crown fabricated by the lab team. Emergence profile and function were established for the patient, along with a very positive long-term prognosis (Figure 31).
DISCUSSION
The Straumann BLT Dental Implant System, used in this clinical case, has a relatively simple protocol that promotes primary initial stability in hard tissues throughout the mouth, from the Type 1 bone found in the mandibular symphysis area to Type 2 in the posterior mandible to Types 3 and 4 in the pre-maxilla and posterior maxilla, respectively. The tapered design allows for immediate placement following the extraction of nonrestorable teeth. The shape of the implant represents the shape of the natural teeth. These implants are made using titanium-zirconium material (Roxolid) that provides high tensile strength, allowing for the creation of smaller diameter implants with a similar clinical performance to larger diameter titanium implants. Osseointegration is promoted by using SLActive surface technology that may help reduce healing time up to 3 or 4 weeks. The internal design of the implant is a cross-fit connection that eliminates rotation and abutment screw loosening.
In situations where the hard tissue has been compromised to a certain degree, either through loss of facial bone or inadequate bone height, bone grafting procedures are an effective method to build these structures up. Bone volume can be replaced when techniques are properly completed. There are several sources of grafting materials available to the profession. These include autogenous bone grafts (grafts harvested from the patients themselves), allografts (grafts taken from a donor of the same species), alloplastic materials (ceramic, hydroxyapaptite, tricalcium phosphates, or calcium phosphates), and xenografts (grafts from another species).4 The bone grafting procedure was used for the case presented herein to resolve the issue of loss of facial plate of bone. Allograft materials provide osteoconduction; the graft material itself serves as a scaffold for new bone growth, which is then perpetuated by natural bone. Osteoblasts from the margins of the native bone defect use the graft material as a framework to generate new bone formation. Some materials provide osteoinduction where progenitor cells differentiate into osteoblasts, which begin the formation of new bone. Bone morphogenic proteins, potent inductors of osteogenic activities (osteoinductive) are active during bone repair. New osteoblast activity is stimulated, thus promoting faster integration of the graft material.5
A barrier membrane is used to allow osteogenic cells to reorganize the bony defect and prevent invagination of epithelial cells. The resorbable membrane is passively positioned on the facial aspect of the bone to promote predictable bone growth. The attached gingiva is reflected to expose the entire defect, and the membrane is placed at least 2.0 mm apical and mesial and distal to the defective site. This should also be followed on the lingual side.
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CLOSING COMMENTS
Today’s advanced implant design and surface processing provide for well-integrated and stable fixtures. Implants have certainly become a remarkable treatment option to create form and function for our patients, even in the aesthetic zone. This reasonably conservative approach, as compared to conventional crown and bridge preparation, makes sense to many of our patients. CBCT 3-D imaging provides treatment planning software that helps in the diagnosis and planning of our cases. Predictable bone grafting results can be achieved using allograft materials protected by a resorbable membrane. With proper technique, form and function can be reliably created.
Dental implants have become mainstream and an excellent treatment modality for the replacement of one to several missing teeth. Dental implants provide an alternative to more conventional dental therapy. Patients tend to navigate to those dental professionals who can provide treatment modalities that improve their quality of life via the creation of pleasing aesthetics and excellent function.
References
- Lang NP, Löe H. The relationship between the width of keratinized gingiva and gingival health. J Periodontol. 1972;43:623-627.
- Schiegnitz E, Moergel M, Wagner W. Vital life-threatening hematoma after implant insertion in the anterior mandible: a case report and review of the literature. Case Rep Dent. 2015;2015:531865.
- Chen ST, Buser D. Clinical and esthetic outcomes of implants placed in postextraction sites. Int J Oral Maxillofac Implants. 2009;24(suppl):186-217.
- Oporto VG, Fuentes FR, Álvarez CH, et al. Maxillomandibular morphology and physiology recovery: biomaterials in bone regeneration. Int J Morphol. 2008;26:853-859.
- Laurencin C, Khan Y, El-Amin SF. Bone graft substitutes. Expert Rev Med Devices. 2006;3:49-57.
Dr. Engel is the founder of the Engel Institute and the Engel Dental Center in Charlotte, NC. In the past 15 years, he has been instrumental in teaching more than 8,500 alumni doctors who have produced more than 300,000 successful implant surgeries. Additionally, Dr. Engel has owned and operated 3 successful practices in his long tenure. He can be reached at drengel@engelinstitute.com.
Disclosure: Dr. Engel reports no disclosures.
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