Written by Dale Herrero, DDS Sunday, 31 August 2003 19:00
For years, the sole goal of dental implantology was to replace missing teeth. Replacing missing teeth with implants dates to Egyptian times, where mummies have been found with ivory tooth implants. The long-term fixation of the implant to bone, known as osseointegration, was the primary objective.1 It was not until professor Branemark published his work in 1983 that the general dental population accepted dental implants to be a predictable technique.2 Aesthetics was not the primary emphasis. Today, however, longevity and function are highly predictable, and aesthetics is now a primary objective. In particular, enhanced aesthetics for single teeth and their soft-tissue covering are the norm.3 The presence or absence of a major malocclusion will usually dictate whether to open space for tooth replacement or close the space. Closing the space usually requires reshaping the substituted teeth as needed for aesthetics.4
|Figure 1. Preoperative views|
|Figure 2. Retained and loose primary cuspid, “C,” with no underlying permanent cuspid. Gingival recession and rotation of tooth No. 5.||Figure 3. Retained and loose primary cuspid, “H,” with no underlying permanent cuspid. Gingival recession and rotation of tooth No. 12.|
|Figure 4. Maxillary arch collapse due to small primary cuspids.|
A team approach including the dentist, surgeon, orthodontist, and patient often best serves the patient.5 No clinician can be an expert in all fields of dentistry.6 Careful coordination of the orthodontist’s, surgeon’s, and restorative dentist’s responsibilities can significantly reduce the total treatment time.7 The restorative dentist accepts the responsibility of referring the patient to other members of the dental team and must be accountable for coordinating each step in the treatment process. The team must understand and embrace the patient’s vision of the final outcome. Initially, the patient places his or her trust in the restorative dentist. Psychologists have found that trust is transferable. Therefore, all the members of the dental team must recognize and accept the importance of this transferred trust.6
|Figure 5. Maxillary arch expansion for aesthetics and function, leaving the ideal mesial-distal space required for full-size cuspids.|
|Figure 6. Removal of primary cuspid with peritomes, requiring no incisions or sutures.|
|Figure 7. Immediate placement of the implant by first determining the ideal location of the CEJ of the final cuspid crown height.|
The specialists have the responsibility to educate the restorative dentist in their specialized area, and the restorative dentist must teach the specialists the “big picture”; ie, the final objective that is to be achieved by the coordinated efforts of each team member. The dentists involved must commit to the extra time involved, trust each other enough to express their ideas and feelings, commit themselves to the agreed upon treatment plan, and support each other during treatment.6
This article discusses orthodontic considerations as a prerequisite to implant replacement. A case report is presented that emphasizes the importance of this concept in the replacement of congenitally missing cuspids in an adult patient. This case started with the orthodontist, who referred the patient to the restorative dentist, who in turn assembled the team to provide the ultimate dental care to the patient.
|Figure 8. Measuring from the location of the CEJ of the proposed cuspid, the platform of the implant is measured to be located 3 mm apical to that location.|
As noted, for years the goal of implantology was to replace missing teeth. Longevity and function were the emphasis; aesthetics was an afterthought. The profession already had a proven track record with fixed prosthetics. However, with the benefits of fluoride and its reduction of caries, patients often present with virgin abutment teeth. Nordquist and McNeill8 found a greater occurrence of gingival irritation and pocket depth with prostheses as compared with individual teeth. Therefore, replacement of a single missing tooth with an implant versus a fixed prosthesis that requires preparation of abutment teeth should be considered.
|Figure 9. Two acrylic denture teeth were adjusted and bracketed to the archwire. This doubled as the patient’s provisional restoration immediately post implant placement.|
In a survey of 6,000 orthodontic cases, Rose found that in 4.3% of cases, the patients had congenitally missing teeth (excluding third molars).9 Before implant placement is considered in such situations, the age of the patient is of paramount importance. If implants are placed in a growing individual, there is a risk of the surrounding bone and teeth changing. This could leave the implant in a submerged position, compromising the aesthetics and crown/implant ratio.10
|Figure 10. Immediately following orthodontic debanding, a vacuform retainer with 2 denture teeth inserted was used both as a retainer as well as a provisional.||Figure 11. After initial settling of the teeth post orthodontics, new models were taken and mounted in centric relation. The occlusal discrepancies were noted and then adjusted in the mouth.|
|Figure 12. Healing abutments in place and the occlusion is adjusted.|
During a thorough patient examination, proposed implant placement is based on both function and aesthetics. Garg found that 2 considerations are essential to the success of using implants to replace missing maxillary incisors: adequate space between teeth and sufficient bone volume in the alveolar ridge.5 The orthodontist needs to move the crowns of the existing teeth to their ideal positions to create the proper mesial-distal distance for the properly sized replacement crown, and move roots far enough apart to allow safe implant placement. Inadequate separation of the adjacent teeth may require interdental enamel reduction for proper tooth size and/or proper occlusion.11
It is imperative that the orthodontist consults with the restorative dentist and surgeon prior to debanding so that any further tooth movement can take place without the patient experiencing unnecessary rebanding or additional orthodontic appliances.12 Nordquist and McNeill8 found that cuspid-guided occlusion often could not be obtained by orthodontic treatment. However, the periodontium of teeth in group function was as healthy as it was in cuspid-guided occlusion. Careful orthodontics and follow-up occlusal adjustments of premature contacts and balancing interferences are imperative.11
|Figure 13. At-home bleaching completed.|
|Figure 14. Porcelain veneer preparations on teeth Nos. 7 through 10.|
|Figure 15. Transfer assemblies placed on No. 6 and No. 11 and ready for impressions for restoration Nos. 6 through 11.|
Osseointegration of dental implants depends on the volume, position, and density of the bone. Additional bone may be grafted, with autogenous bone being the “gold standard.” The density of the bone may be improved with the use of osteotomes during implant placement. It has been suggested that in soft, spongy-type bone, allowing longer than the traditional 6-month integration period may be prudent.2
The implantologists must work as a part of the team, with the restorative dentist acting as the “quarterback.” Space maintenance is critical for these implant cases because of the long-term nature of treatment. The adjacent teeth need to be close to their final positions so there is enough room for the surgeon to place the implant, avoid contacting the adjacent roots, and achieve the ideal mesial-distal position.
|Figure 16. Implant custom abutments placed on No. 6 and No. 11. Individual PFM crowns cemented on Nos. 6 through 11.||Figure 17. Final multidisciplinary result.|
Delayed treatment often results in uncontrolled drifting of teeth, causing aesthetic and occlusal problems.7 If the dental team does not stay in close communication, progress can become uncoordinated, resulting in delays. (Note: an argument for fixed prosthetics could be made that immediately after orthodontic completion, a fixed provisional restoration could be placed to prevent any unwanted tooth movement. If plastic denture teeth are included as part of the retainer, there is a better chance of patient compliance.)13
The following case is an excellent example of how orthodontics can be important to the final outcome of treatment involving single tooth implants. In this case, a 35-year-old female patient initially presented to the orthodontist, who realized the limitations of orthodontic tooth movement alone in treating this patient. The patient was referred by the orthodontist to me (a restorative/implantologist), and I reviewed the case. Upon accepting the case, I then took responsibility as coordinator of the case. The patient was first referred to a periodontist for specific tissue concerns. She then returned to me for final treatment planning before returning to the orthodontist for initiation of orthodontic therapy. By following this process, the patient knew before she started treatment what could be done, what the limitations and risks were, how long the treatment would take, how much it would cost, and what her options were. She received a complete diagnosis with all disciplines being considered and fully disclosed.
The patient was a 35-year-old female in good health (Figure 1). She was motivated to seek treatment because her retained primary cuspids had become loose (Figures 2 and 3). Since her child was having orthodontic treatment, she asked the orthodontist to examine her own mouth. The orthodontist realized that to accomplish ideal aesthetics and function for this patient, a multidisciplinary approach would be necessary. He immediately referred her to me. A comprehensive exam was performed, including tomograms. Examination revealed shortened primary cuspid roots with no permanent cuspids. There was inadequate space for full-size cuspids. There was mild maxillary crowding with maxillary bicuspid rotations. The overjet was 5 mm and the overbite was moderate. The midlines were off by 2 mm. Tissue heights were less than ideal, with recession on the maxillary first bicuspids (Figure 4).
Tomograms revealed enough existing bone for narrow implants if osteotomes were used for some ridge expansion. For larger implants, it would be necessary to graft bone, prolonging treatment and risking the loss of the interdental papillae. Immediate implants without the reflection of a flap would maintain blood to the thin alveolar plate. Placing healing abutments at the time of implant placement would help maintain the height of the interdental papillae.
The differential diagnosis included the following: (1) no treatment, which must always be offered; (2) a removable partial denture; (3) fixed bridgework, either bonded or conventional PFM; or (4) dental implants. After thorough examinations and communication among the orthodontist, periodontist, and myself, the treatment options were proposed, with the costs and time of treatment presented. After reviewing the pros and cons, the patient elected to proceed with dental implants without grafting. The patient knew that her decision involved a considerable amount of time, inconvenience, and expense. However, she was well aware that her dental situation had been carefully considered by several different dentists, each with their different experiences, viewpoints, and biases but with the patient’s best interests in mind.
The periodontist proposed that the gingival recession on teeth Nos. 5 and 12 be corrected with connective tissue grafts before orthodontics was started. He felt that in this case, the patient was at risk for further gingival recession during orthodontic movement.
Treatment was begun by the periodontist, who took connective tissue from the patient’s palate and placed it on the labial of teeth Nos. 5 and 12. After initial healing, the orthodontist placed gold-plated brackets on the maxilla and mandible. The gold-plated brackets have a softer, more aesthetic appearance than standard silver brackets.
After the spaces for teeth Nos. 6 and 11 were opened, it was decided to place the implants and finish the minor detailing of the occlusion while the implants were integrating, thus saving the patient several months of total treatment time. I asked the orthodontist to band the primary cuspids 1 week prior to extraction to loosen them and make removal easier (Figure 5). The primary teeth were then extracted atraumatically with the use of a periotome and forcep, without incisions or elevation of flaps (Figures 6 and 7).
With the use of spade drills and osteotomes, the osteotomies were formed. Because the bone was not exposed, it was imperative to identify the level of the bony crest in order to determine exactly where to place the necks of the implants for proper emergence profile. The goal was to place the top of the implant 3 mm above where the CEJ of an ideal cuspid would normally be. First, an aesthetic line based on the centrals and laterals was drawn to establish the ideal CEJ, then a mark was made on the tissue 3 mm above the aesthetic line (Figure 8). Next, the distance from the gingival crest to this mark was measured. With the use of a periodontal probe, it was possible to determine when the implants had been inserted to this depth. Two Steri-Oss Replace Select 3.5 x 16 mm HA-coated implants (Nobel Biocare) were placed. Healing abutments were placed to support the interdental papillae.
For temporization during healing, the orthodontist had prepared 2 denture teeth with brackets to be added to the arch wire after implant placement. These were adjusted to prevent them from being visible but not impinge on the healing abutments (Figure 9).
During finalization of the orthodontics and healing of the implants, the patient decided to expand treatment to achieve a more complete smile makeover. She had an existing mesial-incisal (MI) composite on tooth No. 8 and an MI chip on tooth No. 9. The lateral incisors were undersized and the gingival architecture was slightly unbalanced.
The orthodontic treatment was completed in 14 months, requiring 19 orthodontic visits. A clear, vacuum-formed retainer was delivered when the bands were removed. In the retainer, the orthodontist had placed 2 denture teeth to replace teeth Nos. 6 and 11 (Figure 10). After initial settling of the teeth, the orthodontist remounted the models on a semi-adjustable articulator in the patient’s centric (hinge-axis) relation (Figure 11). After studying the prematurities on the mounted models, he then went to the mouth and made the necessary occlusal corrections to achieve centric (maximum intercuspation) occlusion that was identical to centric relation (Figure 12).
A regiment of at-home bleaching was completed, and the patient was now ready for restorative treatment (Figure 13). At the first restorative appointment, the gingival tissue was lightly contoured with an electrosurgical machine, being careful not to touch the implants. Teeth Nos. 7 through 10 were prepared for porcelain veneers, transfer copings were placed on the implants replacing teeth Nos. 6 and 11, a polyvinyl siloxane impression (Imprint II, 3M ESPE) was taken of the maxillary and mandibular arches, and the impression was sent to the dental laboratory (Figures 14 and 15).
One month later, the implant abutments were placed and torqued to 35 ncm. The PFM crowns were cemented with Vaseline and Improv cement (Nobel Biocare). The veneers were bonded with Optibond (SDS/Kerr) and Variolink (Ivoclar Vivadent) (Figures 16 and 17).
To be successful, implant dentistry must be multidisciplinary, with aesthetic prosthetics driving the ultimate treatment plan. The presented case shows how a successful result can occur if all aspects of dentistry are considered and the appropriate practitioners are consulted at the beginning of treatment rather than late in treatment, when the patient’s options may be limited.F
The author would like to acknowledge the following members of the treatment team for the case presented in this article: Straty Righellis, DDS, orthodontist (Oakland, Calif); Keith Chertok, DDS, periodontist (Oakland, Calif); and Uwe Brosamie, laboratory technician (Sacramento, Calif).
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10. Haines WF. Osseointegrated implant to replace a missing lateral incisor following orthodontic treatment. Br J Orthod. 1990;17:355.
11. Roth PM, Gerling JA, Alexander RG. Congenitally missing lateral incisor treatment. J Clin Orthod. 1985;19:258-262.
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