Immediate implant placement and immediate loading after a complicated tooth extraction
As implant dentistry continues to evolve to meet our patient’s demands for aesthetic tooth replacements with minimal downtime or inconvenience, the dental implant industry has responded with new technological advancements and research. For example, the development of enhanced implant surfaces, such as the Osseotite Dual-Acid-Etched Implant Surface, improved on the results seen with machined surfaced implants.
Studies demonstrated long term Cumulative Survival Rates (CSRs) with Osseotite implants in the range of 95% to 98%1–3 (at five years4) which represented an improvement over the CSRs of machined surfaced implants (85% to 95%).5–6 With these enhanced implant surfaces, clinicians felt confident to perform early loading protocols and to place implants in compromised clinical situations. With multicenter, long term prospective studies and the ten year history of Osseotite, good long term success with negligible peri-implant concerns has been demonstrated.3
With such positive results, why do researchers and the dental implant industry continue to look for advancements in implant surface technology and designs? Implants typically demonstrate good initial primary stability at the time of placement, however, when bone remodels in the first few weeks following implant placement, primary implant stability can degrade with initial bone resorption which in turn might impact the ability to successfully perform immediate loading protocols. To potentially address this concern, new nanotechnology in implant surface topography has been explored. BIOMET 3i has been the first implant company in introducing a nano-textured implant surface, the NanoTite obtained by applying nanoscale crystals of calcium phosphate onto the Osseotite surface by using a Discrete Crystalline Deposition (DCD) Process. This process creates a more complex surface topography which renders it a Bone Bonding surface by the interlocking of the newly formed cement line matrix of bone with the implant surface. The result: a more rapid bone formation with improved bone-to-implant contact (BIC) as demonstrated in animal studies and human histology.7,8 What is the significance of these findings in clinical practice? Clinicians can immediately load the implants, reduce the time to loading and treat more patients even in compromised clinical situations, such as poor bone quality, limited bone quantity, or in grafted sites.
What about crestal bone preservation?
Preservation of crestal bone has proven to be critical for long term implant success. This is especially true in the anterior aesthetic zone for support of the peri-implant soft tissues, as well as in areas of limited bone height so as to maximize bone-toimplant contact. One new implant design available today, such as the NanoTite Prevail Implant, has built in platform switching with the surface treatment to the top of the implant collar at the medialisation point, creating a continuous bone loading surface allowing for this crestal bone preservation.9–11 This implant has been designed with straight and expanded collar configurations. The straight collar configuration is ideally suited for sites with limited restorative space, such as missing maxillary lateral incisors or mandibular anteriors. The expanded collar configuration was used in the following clinical case and is indicated for sites where engagement of the crestal cortical plate of bone is required to achieve a high level of primary stability.
A 45-year-old female patient presented with the upper right milk canine (tooth 53) affected by caries, which caused an important occlusal and distal destruction and pulpar necrosis (Fig. 1).
Figs. 1 & 2: Initial situation: caries destruction of upper milk canine and included canine underneath.
The radiographic examination revealed an included final canine (tooth 13) and a minimum root support of the milk canine but no presence of periapical defects (Fig. 2). The patient desired a fast and aesthetic restoration of the affected tooth.
The exploration revealed a preserved buccal bone plate which allowed for the extraction of the included canine and immediate placement of a dental implant with immediate non-occlusal loading with a temporary crown, which would last for four months until the final crown would be inserted.
On the day of the surgery, the extraction of the milk and the included canines was made after an intra-sulcular palatal incision from the first upper premolar to the central incisor to allow for a good visibility of the area to treat. The extraction of the canine required a previous osteotomy and the section of the tooth. The socket walls and bone defect were debrided before initiating the drilling for the implant placement (Figs. 3 & 4).
Figs. 3–8: Extraction of the milk and the included canines (Figs. 3 & 4). Implant in final position with palatal bone grafting (Figs. 5 & 6). Impression making for the provisional restoration (Fig. 7). Provisional crown in place (Fig.8).
After a meticulous drilling sequence, a Nano-Tite Prevail Certain implant 4mm in diameter and 13mm in length (BIOMET 3i, Inc.) was slowly inserted with the drill unit at 40 Ncm torque, maintaining the direction of the osteotomy (Figs. 7 & 8). This implant, thanks to its expanded collar shape, is ideal to seal the access to the alveolus, to achieve optimal coronal stability and to preserve the crestal bone thanks to the integrated ‘platform switching’. The palatal bone defect was filled with the bone chips collected from the drilling in a bone filter (Fig. 6).
A 5mm emergence profile impression coping was placed and the tissues were sutured around it (Fig.7). Then an impression was made and sent to the laboratory for the fabrication of the provisional crown while a healing abutment of the same size was left in mouth.
The following day, the out-of occlusion provisional crown was made with a titanium hexed provisional UCLA cylinder (BIOMET 3i), resin was inserted and the access hole closed with light-curing composite (Fermit) (Fig. 8). A periapical radiograph for crestal bone levels control was taken (Fig. 9).
Figs. 9–11: Initial periapical radiograph (Fig. 9). Control after four months (Fig. 10). Soft tissues after provisional crown retrieval (Fig. 11).
The patient came back for periodic controls after one, two and four months after provisional crown insertion (Fig.14).
At the fourth months control, the provisional crown was retrieved observing the ideal emergence profile created (Fig. 11). A final impression was made and sent to the laboratory for the final crown production.
Five months after implant insertion the final screw-retained porcelain-fused-to-metal crown, made from a machined gold alloy Certain UCLA cylinder (BIOMET 3i), was inserted (Fig. 12). A periapical radiograph was taken to control the interproximal bone levels which showed less than 0.5 mm bone remodelling mesially and no bone remodelling distally.
Figs. 12 & 13: Final crown insertion and radiograph at five months.
Six months after implant insertion the patient came back for control. We can observe in Figure 14, that the small defect in the distal papilla had been corrected during this time, mainly thanks to the respected maximum distance between the interproximal bone crest and the contact point of the crowns. One year after tooth extraction and implant placement the patient showed optimal aesthetic results with the papillas fully covering the interproximal spaces, a full bone regeneration of the palatal defect and optimal crestal bone preservation (Fig. 15).
Figs. 14 & 15: Healing after six months (Fig. 14). Final result after one year (Fig. 15).
As demonstrated in the clinical case, the new implant designs available today with the nano-textured implant surface, allows to replace lost teeth immediately and place a provisional restoration also immediately even in complicated tooth extractions which require bone grafting at the same time. Thanks, among other factors, to the platform switching included in the coronal implant macro design, the peri-implant crestal bone and thus the optimal aesthetic result obtained can be preserved over time.
Editorial note: A complete list of references is available from the publisher. This article was originally published in Cosmetic Dentistry Vol. 2, Issue 3, 2008.
Dr Xavier Vela
Barcelona Osseointegration Research Group (BORG)
Tel.: +34 93 8675822