Implants are indicated for single and multiple tooth replacement. In most cases, implant therapy is far more conservative than crowns and bridges in replacing the missing dentition. Implant dentistry started slowly in the 1980’s but has grown tremendously over the past few decades as patient and practitioner became aware of its inherent advantages. The spread of clinical implantology to the general practice (it was initially recommended only for specialist use) has greatly increased its public visibility and availability. The prospect of restoring functional and esthetic dentition for the partially or totally edentulous has greatly improved the public’s perception both of the profession and the various available treatment options. Now that dental implants are well accepted by mainstream dental practitioners and the procedure has become well established, the profession is turning its attention to other further challenges within this treatment modality. Today, one of the most important challenges in implant dentistry is the attainment of not only a functional but also an esthetic result when restoring cases in the esthetic zone.
The esthetic zone can be referred to as to any area that is visible when the patient is smiling. This means that the esthetic zone extends at least up to the first bicuspids both on the maxillary and the mandibular arches in patients, and frequently to the second bicuspids and first molars, as well. Thus, most dental treatments are within the esthetic zone simply because the restored dentition can be seen when the patient opens their mouth or smiles. As patients have become more aware of the role and the opportunities of implant treatments, they are increasingly demanding not only functional, but esthetic results.
In order to thoroughly evaluate a new patient’s needs, a comprehensive dental examination must first be performed. This includes dental and medical questionnaires, pre-operative pictures, an appropriate series of radiographs, maxillary and mandibular impressions with a bite registration and a 3-dimensional cone beam scan that reveals much information that may otherwise be hidden from the dentist’s view. The goal of the evaluation is to establish a comprehensive treatment plan with the patient’s functional and esthetic objectives in mind. The first choice is always the optimal treatment plan, but this may, in many cases be tempered by the patient’s health, socio-economic situation and time availability.
The dental team has an obligation to present a series of suitable treatment plans, including the optimal plan, as alternative solutions for the patient’s decision-making. The presentation of the treatment plan includes education about relative benefits, risks and costs of each of these alternatives. This ensures that the patient is well informed and capable of making an appropriate decision.
An objectively organized approach to the treatment planning assures that the dentist and the dental team does not make any inappropriate assumptions about the patient’s expectations, health, or financial limitations. From a practical perspective, it is essential to align the treatment options with the professionals’ ability to deliver these results within the contexts of the patient’s general and oral health, and financial realities.
CASE PRESENTATION
A 40-year-old female presented at the practice for a general consultation. The patient had previously visited another practitioner and was quite aware about the various dental technologies that were available for her particular situation from her own research. The patient’s smile (Figs. 1, 2), left lateral appearance (Fig. 3), and frontal view of occlusion (Fig. 4) indicate the pre-treatment status of her teeth. The panoramic view (Fig. 5) revealed eight teeth that had been endodontically-treated: the upper right first molar, the upper left first and second bicuspids and second molar, the lower left first and second bicuspid, and the lower right first and second bicuspids. Some of these teeth had residual infections and some of the endodontic treatment was questionable in light of current standards. The upper right second molar, the upper right first bicuspid, lower left first molar and lower right first molar were missing. As indicated in (Fig. 3), the maxillary left premolars had extruded. The extrusion of the upper left premolars had not only affected the occlusal relationship but had altered the supporting alveolar bone, as well.
Underneath the cantilevered pontic for the upper right first bicuspid there was a large concavity of bone resorption in the buccal vestibule as seen in (Fig. 6). The numerous problems that exhibited in the patient’s mouth required fairly extensive treatment planning; the patient requested the most optimal treatment sequence.
After a thorough study of all of the patient’s records, which included the health and dental questionnaires, the mounted impressions, a full set of radiographs, and a 3D cone beam scan, a final treatment plan was established:
• The removal of the upper right first molar, the upper left first and second bicuspids and the upper left second molar.
• The bridge on the upper right was cut to eliminate the cantilever pontic from the first molar to the first premolar area. The bridge on the lower left was also cut to separate the pontic from the lower left first molar and the removal of the lower left first bicuspid. This segment of the treatment plan involved ridge expansion and particulate bone grafting with Cerasorb/Curasan. (Fig. 7)
• The leveling of the bone extrusion on the upper left bicuspid area. (Figs. 8, 9, 10, 11)
The placements of implants as indicated in Table 1.
THE FULL MOUTH RESTORATION COULD PROCEED
It is generally a good idea when grafting particulate bone into the socket to wait a period of 4-6 months before placing any implants. For this patient, the implants were placed using a surgical guide made from the initial wax-up of the patient’s original dentition and based on the 3 dimensional scan. This was done to ensure the particulate bone had integrated well and that the hard and soft tissues had healed. Flapless surgery was acceptable for the upper left first and second bicuspid, upper left second molar and the lower left second molar. (Figs. 12, 13, 14) Flap implant surgery was required for the upper right first bicuspid, and lower left first bicuspid because ridge expansion and particulate bone was needed at the time of implant placement. (Figs. 15, 16, 17, 18) The preparatory work was done with a 3-D cone beam which developed a computer generated surgical guide that assured ideal positioning when placing the implants, and guaranteed an optimal relationship of the final restorations within occlusal, functional and esthetic parameters.
The recommended protocol for the Ankylos Implant System (Dentsply Tulsa Dental Specialties) requires the placement of the implants to be 0.5mm to 1.5mm subcrestal in order to reduce cortical plate trauma and to create an ideal crown emergence profile. With the Ankylos system, the implant/abutment interface is a conical connection with a precise Morse Taper, which is friction locked, thus preventing micro-movement irritation and eliminating micro-gaps that develop in other systems. The absence of the micro-gap effectively seals the abutment/implant interface off from bacterial colonization, a major cause of bone die-back. The Ankylos system also eliminates the odors commonly observed with other implant systems when the abutment is removed from the implant. Odor often occurs because even a microscopic back and forth rocking of the abutment within the implant can pump in liquids that include bacteria and oral fluids which can be trapped in the space between the implant and the abutment. There, various chemical reactions can occ
ur. These spaces are, of course, impossible to clean (for either patient or dentist). Implant components can only be cleansed and disinfected when the abutment is removed from the implant. The problem however will begin anew when the abutment is replaced and the patient begins loading the restoration during normal function. The bacterial and chemical insults from the constant inspiration and expiration of liquids in and around the implant abutment interface irritate the surrounding bone, causing the bone to recede. In extreme situations, this can also cause the bone integration of the implant to fail, resulting in the loss of the entire implant structure.
The design of the Ankylos implant system leaves space in the vicinity of the tapered abutment for the soft tissues and bone to grow around the implant shoulder, effectively preventing the bone and soft tissue loss seen in many conventional abutment joint implant designs. The restorative phase of treatment begins once the implants are osseointegrated. (Fig 19) SECOND STAGE TREATMENT
The second stage of treatment begins with the exposure of the implants and the placement of the healing abutments (known as sulcus formers in the Ankylos system). The role of the sulcus formers is to condition and shape the soft tissue to provide a healthy, uniform emergence profile, which is then prepared to receive the final abutment of the restoration. The final abutments, chosen chairside in this case, were selected two weeks after the sulcus formers were placed using an abutment try-in kit. (Fig. 20) For this patient, standard abutments were selected (Fig. 21), and they were torqued down to a value of 25 nCM. This torque is lower than what is commonly used for many implant systems, but is suitable for Ankylos implants because of the strength of the Morse Taper connection. The Morse Taper essentially converts the two segments of the implant system into one; the resulting two component system mimics a single piece implant that does not allow any movement or rocking between the components. Once all the teeth are prepared, transfer copings are connected to the final abutments. (Figs. 22, 23) Each transfer coping color corresponds with the color of the abutment in the trial kit. Full arch impressions are then taken with vinyl polysiloxane (Flexitime Heavy Tray, Heraeus Kulzer). Full mouth provisional restorations are fabricated to maintain a limited function and aesthetics while the permanent restorations are completed at the laboratory. (Figs. 24, 26, 26) At this stage adjustments and modifications to both function and aesthetics were made to both the practitioner’s and the patient’s satisfaction. Once all the necessary adjustments were completed and the patient was totally comfortable, the occlusal registration was taken for the vertical dimension. Impressions of the provisional restorations were taken and sent to the laboratory technician to ensure a predictable result according to the patient’s functional and aesthetic requirements in the final restoration. (Figs. 27, 28)
COMPLETED RESTORATIONS
The final restorations were made of ceramic (Press Ceram to Zirconia Swiss NF Metals) with a zirconium core (YZ Vita).
The provisional restorations were removed and the teeth cleaned with pumice. The final restorations were tried in to the patient’s mouth and verified for both function, esthetic position and shade alignment. At the last stage, the final restorations are then cemented with a glass inonomer luting cement (FujiCEM Automix GC). All final adjustments are made to assure the dentition is occlusally and functionally acceptable.
Since all the abutments used in this case are Standard Abutments from the Ankylos system selected chairside, they stay in the patient’s mouth permanently from the impression stage until cementation and beyond. These abutments are the ones up on which the permanent crowns are cemented. The final result is a very satisfied patient with an excellent aesthetic smile, a functional occlusion, and as an ideal harmony of size, fit and color. (Figs. 29, 30, 31, 32)
This result is dependent on;
• a well developed treatment plan;
• the utilization of 3-D cone beam scan technology to establish a com- prehensive treatment plan and surgical guidance that avoids treatment errors and complications;
• an implant system that is patient-friendly and easy to use for both the dental practitioner and the laboratory technician;
• the use of an implant system (Ankylos) that avoids post-treatment bone loss in the implant area and maintains the bone level and functional and aesthetic parameters for extended period of time after treatment.
REFERENCES
1. All Ankylos “Classic Surface” supporting data in JOI Volume 30, Number 3 2004 and in 501(k)s.
2. Nentwig GH: The Ankylos Implant System: Concept and Clinical Application. J Oral Implantol. 2003;30 (3): 171-177 .
3. WeigI P: New Prosthetic Restorative Features of the Ankylos Implant System. J Oral Implantol. 2003; 30 (3):178-188.
4. Doring K, Eisenmann E, Stiller M : Functional and esthetic considerations for single-tooth ANKYLOS implant-crowns: 8 years of clinical performance. J Oral Implantol. 2004; 30 (3): 198-209.
5. Eisenmann E, Stiller M, Doring K, Fritz H, Freesmeyer WB: Das Ankylos Balance -Aufbausystem. Quintessenz 1999; 50 (6):583-596.
6. Morris HF, Ochi S, Crum P, Orenstein IR. Winker S: AAIRG, Part 1: Multicentered, Multidisciplinary Clinical Study of a New and Innovative Implant Design. J Oral Implantol 2003: 30(3): 125-133
Dr. Tam Phan graduated with honorable mention from the University of Laval, and is a Fellow of the ICOI. He has since been trained by pioneers in the field of dental implantology and bone grafting such as Dr. Douglas Deporter at the University of Toronto, Dr. Dennis Smiler and Dr. Carl Misch. He has won many awards for his work including the Prix Fondation Guy Maranda for excellence in oral surgery. He is a member of the International Congress of Oral Implantologists, the Canadian Society of Oral Implantology, the American Academy of Cosmetic Dentistry and more. His private practice in Kirkland, Quebec is focused on implantology and cosmetic rehabilitation.
Dr. George Freedman is a founder and past president of the American Academy of Cosmetic Dentistry, a co-founder of the Canadian Academy for Esthetic Dentistry and a Diplomate of the American Board of Aesthetic Dentistry. Dr. Freedman sits on the Oral Health Editorial Board (Dental Materials and Technology) is a Team Member of REALITY and lectures internationally on dental esthetics and dental technology. A graduate of McGill University in Montreal, Dr. Freedman maintains a private practice limited to Esthetic Dentistry in Markham, Ontario.
The authors of this article wish to thank Anas Raffoul from Laboratoire R.B. for his meticulous work on the restorations.
Oral Health welcomes this original article.
