Treatment strategies for infraoccluded dental implants Nicola U. Zitzmann, DDS, PhD,a Dario Arnold, Med Dent,b Judith Ball, Dr Med Dent,c Daniel Brusco, Dr Med, Dr Med Dent,d Albino Triaca, Dr Med Dent,e and Carlalberta Verna, Prof Dr Med Dentf The use of dental implants to ABSTRACT replace single missing teeth Single-tooth implants in the maxillary anterior region have the highest risk of esthetic complications was established in the 1980s, from infrapositioning due to continuing maxillary growth and the eruption of adjacent teeth. and 97% success rates were Although the placement of anterior single-tooth implants should normally be postponed, particreported at the 5-year followularly girls and young women with a hyperdivergent growth pattern, if an infraposition of an up.1 At that time, it was implant is present, then thorough examination and strategic planning are required. According to the severity, the strategic treatment options are as follows: simple retention; adjustment or already known that, in actively replacement of the implant restoration, possibly including adjacent teeth; surgical implant repogrowing patients with onsitioning by segmental osteotomy combined with osseodistraction; or submergence or removal of going maxillary skeletal and the implant. With the patient presented, an interdisciplinary approach that combined orthodontic dental growth, osseointegrated alignment, surgical segmental osteotomy, distraction osteogenesis, and restorative features offered implants do not adapt to pothe opportunity to realign the adjacent teeth into the arch and to harmonize the gingival contour sitional changes of the natural by means of continuous soft tissue enlargement and adaptation. (J Prosthet Dent 2015;113:169-174) dentition. Similar to ankylosed lengthen as the mandibular inclination increases and teeth,2 implants remain stationary in the bone and do not the maxilla elongates to compensate; this places follow the changes of the alveolar process with continwomen at greater risk of implant infraposition.12,13 uous eruption of the natural dentition.3,4 This inability to Particularly individuals with a hyperdivergent growth move with the adjacent teeth causes deﬁciencies in the pattern (long face type) tend to have more pronounced alveolar bone and surrounding gingival tissues and leads maxillary growth and a backward rotation of the to a discrepancy in the sagittal and transversal dimenmandible in relation to the cranial base (SN line). The sion, described as infraocclusion or infraposition of the dentoalveolar complex follows this rotation to comimplant.5 pensate, which enhances the vertical movement of the Vertical growth of the nasomaxillary complex with natural dentition.6,11 an anterior and downward displacement of the maxilla Given these patterns of growth and eruption, an usually ceases at the age of 17 to 18 years in girls and increased risk for infrapositioning of maxillary anterior somewhat later in boys.6 However, implant infraposisingle tooth implants has been documented, especially tioning has also been reported in patients who receive in young women and in patients with a long-face implants during adulthood7-10 and is related to the appearance.7-9 Because asymmetry that results from continuous eruption of the teeth, which occurs even 11 an infrapositioned single-tooth implant in this region after occlusal contact is established. From the age of is most visible and esthetic impairment is pro25 to 46 years, men’s faces tend to grow more in nounced, implant placement should be postponed,14-16 posterior height, whereas women’s faces tend to
Professor, Department of Periodontology, Endodontology and Cariology, University of Basel, Basel, Switzerland. Resident, Department of Orthodontics, University of Basel, Basel, Switzerland. Senior Resident, Department of Orthodontics, University of Basel, Basel, Switzerland. d Private practice, Haus zur Pyramide, Zurich, Switzerland. e Private practice, Klinik Pyramide am See, Zurich, Switzerland. f Professor, Department of Orthodontics, University of Basel, Basel, Switzerland. b c
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Table 1. Treatment options for infrapositioned dental implants
Extent of Infrapositiona
None or mild (1 mm)
Adjustment or replacement of implant restoration (and/or adjacent teeth)
Restoration and/or adjacent teeth allow for modiﬁcations
Minimally invasive adjustments
Severe (>1 mm)
Surgical implant repositioning (segmental osteotomy) possibly with distraction
Sufﬁcient width of bony septa required (3 mm); when soft tissue enlargement is required
Prolonged treatment time
Segmental osteotomy not feasible and/or implant removal not indicated
Risk of soft tissue perforation and infection; more predictable with 2-part implants that enable removal of transmucosal portion
Augmentation and staged implant placement and/or alternative restorative treatments
Extended ridge defects, prolonged treatment time
Classiﬁcation according to Jemt et al, based on clinical assessment in sagittal dimension.
and alternative treatment options, including autotransplantation, orthodontic space closure, or a resin-bonded ﬁxed dental prosthesis, should be considered.17,18
Treatment Strategy for Correcting Implant Infraposition To assess the treatment requirements and to select the appropriate treatment to correct an infrapositioned implant, a clinical and radiographic examination should include the following: the severity of the vertical discrepancy (infraposition) related to the equivalent contralateral tooth and the position of the incisal edge and gingival margin of the symmetric contralateral tooth as references; the extent of transversal (bucco-oral dimension) changes of adjacent teeth, which possibly become trapped lingually to the stationary implant restoration; the involvement of the opposing dentition, such as compensatory elongation; and 2- or 3dimensional radiographs to estimate the width of the bone septum, particularly when bone segmentation for osseodistraction is considered. Indications for treatment options depend on the severity of infrapositioning and can be categorized according to their invasiveness (Table 1). Stabilizing the anterior dentition, including the implant with a ﬁxed retainer is considered as a preventive measure to avoid changes due to the continuing eruption of adjacent and opposing teeth. However, if growth continues, then the retention of the maxillary anterior dentition maintains the teeth in a stable position relative to the implant and possibly causes an open occlusal relationship, or with compensatory elongation of the mandibular incisors, a sagittal step between the anterior and posterior dentition may be induced. Modifying the implant restoration and/or the contralateral tooth by grinding or even replacing the implant crown is certainly the least-invasive treatment option and, therefore, the most frequently chosen, THE JOURNAL OF PROSTHETIC DENTISTRY
particularly if the infraposition is minor. This modiﬁcation also can include adjustments to the gingival contour, for instance, by gingivectomy (Fig. 1). Surgical repositioning of the implant by segmental osteotomy,19 possibly in combination with osseodistraction for gradual movements of the bony segment and enlargement of the soft tissues also is an option (Fig. 2) as is removing the implant restoration, submerging the osseointegrated enossal implant portion, and fabricating a resin-bonded or conventional ﬁxed dental prosthesis. Removing the implant and either augmenting for staged implant placement or performing an alternative restorative treatment (resin-bonded or conventional ﬁxed dental prosthesis) also is an option. Segmental osteotomy was described in the 1970s as a way to correct the position of teeth that could not be moved orthodontically.20,21 More recently, several case reports documented its application for surgical implant repositioning.19,22 Distraction osteogenesis combines the segmental osteotomy with a subsequent slow movement along a ﬁxed appliance to overcome the limited stretchability of the deﬁcient soft tissues and, therefore, to facilitate a greater translocation of the mobilized segment. This procedure was originally developed to reconstruct vertical alveolar bone defects accompanied by continuous soft tissue expansion23 and also has been used to relocate an infrapositioned dental implant when the soft tissues have to be enlarged simultaneously through continuous gradual traction of the bony segment.24,25 An interdisciplinary approach that uses an external distractor stabilized with an orthodontic arch wire and that involves the maxillofacial surgeon, the orthodontist, and the restorative dentist is described with reference to a patient with progressive implant infraposition. CLINICAL REPORT A 24-year-old woman reported dental trauma with avulsion of the left maxillary central incisor at the age of 7 Zitzmann et al
Figure 1. Patient (age 32 years, 7 years after implant placement) with severe infraposition (2.5 mm) of implant at right central incisor position. Treatment planning comprised new restorations of both central incisors with preceding gingivectomy on facial aspect of left central incisor. A, Frontal view of clinical situation. B, Periapical radiograph. C, Maxillary anterior teeth assessed for esthetics.
Figure 2. Segmental osteotomy of bone surrounding infrapositioned implant (left lateral incisor position) with parallel vertical incisions in preparation for osseodistraction.
years. The tooth had been repositioned but was removed 3 years later because of external resorption and ankylosis. At the age of 14 years, skeletal growth ceased, and Zitzmann et al
an implant (Standard plus, regular neck, 10 mm length; Straumann AG) was placed at the age of 17 years. After soft tissue grafting, the implant restoration was delivered at age 18 years. Six years later, the patient noticed that the implant restoration was no longer in occlusion and that the implant shoulder was exposed, with gingival recession. Moreover, the adjacent teeth were now lingual to the implant crown. A clinical and radiographic examination revealed that the implant infraposition was 2 mm sagitally (vertical) and 3 mm facially. The gingival recession at the crown margin amounted to 4 mm (Fig. 3A-C). The width of the bone septa on the mesial and distal measured 4 mm and 3 mm, whereas the bone that was apical to the implant measured only 3 mm, which is the minimum for segmental osteotomy.26 Presurgically, a multibracket appliance was ﬁxed from canine to canine to level the anterior dentition and to resolve the lingual displacement of the adjacent teeth. After 1 month, a 0.017×0.022 stainless-steel wire with an apical bypass in the area of the implant restoration was inserted. With the patient under THE JOURNAL OF PROSTHETIC DENTISTRY
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Figure 3. Patient with severe infraposition of maxillary left central incisor implant. A, Frontal view of patient’s smile. B, Infrapositioned implant. C, Occlusal view, showing facial displacement of implant crown. D, Distractor in place after segmental osteotomy. E, Individualized abutment with ﬁxation at adjacent teeth for torque application. F, Ceramic crown cemented. G, Occlusal view with retainer in place. H, Periapical radiograph after treatment was completed.
local anesthesia, surgical access was accomplished by a mesial and distal trapezoidal incision from the mucogingival margin to the vestibule, and preserving the papillary structure. Soft tissues were mobilized by a tunneling preparation that protected the periosteum layer that covered the implant segment. A segmental osteotomy with parallel vertical incisions was performed with a rotating surgical ﬁssure bur and further extended through the medullary and palatal bone with thin osteotomes or chisels until the segment was mobilized. No access was THE JOURNAL OF PROSTHETIC DENTISTRY
made from the palatal side to ensure adequate vascularization. To avoid bone obstructions during movement of the segment, the vertical osteotomies should be positioned parallel or even convergent to the apical region.27 A custom-made external distraction device (Orthognathics GmbH) was adhesively cemented to the buccal surface of the implant crown and to the heavy steel orthodontic arch wire with light-polymerizing composite resin (Fig. 3D). The distractor position and alignment, which determines the vector of movement of the Zitzmann et al
Figure 3. (continued) Patient with severe infraposition of maxillary left central incisor implant. A, Frontal view of patient’s smile. B, Infrapositioned implant. C, Occlusal view, showing facial displacement of implant crown. D, Distractor in place after segmental osteotomy. E, Individualized abutment with ﬁxation at adjacent teeth for torque application. F, Ceramic crown cemented. G, Occlusal view with retainer in place. H, Periapical radiograph after treatment was completed.
mobilized bone segment, should be planned according to the required direction of displacement.27 After a 7-day latency period for callus formation, the distraction of the implant-osseous block was initiated with 0.3 mm of activation per day. The distraction procedure was monitored for 2 weeks until an implant extrusion of 4 mm with a palatal inclination of 4 mm was achieved. The palatal surface and incisal edge of the implant restoration were continuously adjusted to avoid occlusal interference. When the deﬁnitive position was reached, the distractor was removed and replaced with a bracket to facilitate small alignments with a 0.016×0.022 Sentalloy wire (Dentsply Intl) for another 2 weeks. The ﬁxed appliance and a 0.019×0.025 titaniummolybdenum alloy wire (Ormco) were then used to retain the distracted implant during the consolidation period of 3.5 months until bone healing was complete. After debonding the ﬁxed orthodontic appliance, a splint retainer was used for interim stabilization during the restorative treatment. The implant restoration and the angulated abutment were removed, and an impression was made at the implant level. An individualized angulated titanium abutment was combined with a zirconia coping to avoid a grayish discoloration in the marginal area and to facilitate an optimal contour of the crown margin along the undulation of the gingival margin. After clinical evaluation, the zirconia coping was adhesively cemented to the abutment by the laboratory technician. This abutment Zitzmann et al
was then inserted by applying 30 Ncm torque with a temporary ﬁxation on the adjacent teeth (Fig. 3E). The screw access was plugged with a small piece of cotton and white gutta percha (Dentsply Intl). A ceramic crown (IPS e.max; Ivoclar Vivadent) was adhesively cemented (RelyX Unicem; 3M ESPE) and excess cement removed. A ﬁxed wire retainer was cemented onto the palatal surfaces from canine to canine to ensure adequate retention (Fig. 3F-H). SUMMARY Because of the potential for complications from infrapositioning, single-tooth implants in the maxillary anterior should be postponed until mature adulthood. If implant infrapositioning occurs, then surgical segmental osteotomy, combined with orthodontic distractor ﬁxation, distraction osteogenesis (osseodistraction), and restorative treatment, is a valuable option for maintaining the particular implant and improving the soft tissue contour. REFERENCES 1. Henry PJ, Laney WR, Jemt T, Harris D, Krogh PH, Polizzi G, et al. Osseointegrated implants for single-tooth replacement: a prospective 5-year multicenter study. Int J Oral Maxillofac Implants 1996;11:450-5. 2. Kawanami M, Andreasen JO, Borum MK, Schou S, Hjorting-Hansen E, Kato H. Infraposition of ankylosed permanent maxillary incisors after replantation related to age and sex. Endod Dent Traumatol 1999;15:50-6. 3. Cronin RJ Jr, Oesterle LJ, Ranly DM. Mandibular implants and the growing patient. Int J Oral Maxillofac Implants 1994;9:55-62.
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4. Oesterle LJ, Cronin RJ Jr, Ranly DM. Maxillary implants and the growing patient. Int J Oral Maxillofac Implants 1993;8:377-87. 5. Thilander B, Odman J, Grondahl K, Friberg B. Osseointegrated implants in adolescents. An alternative in replacing missing teeth? Eur J Orthod 1994;16: 84-95. 6. Heij DG, Opdebeeck H, van Steenberghe D, Kokich VG, Belser U, Quirynen M. Facial development, continuous tooth eruption, and mesial drift as compromising factors for implant placement. Int J Oral Maxillofac Implants 2006;21:867-78. 7. Andersson B, Bergenblock S, Furst B, Jemt T. Long-term function of singleimplant restorations: a 17- to 19-year follow-up study on implant infraposition related to the shape of the face and patients’ satisfaction. Clin Implant Dent Relat Res 2013;15:471-80. 8. Bernard JP, Schatz JP, Christou P, Belser U, Kiliaridis S. Long-term vertical changes of the anterior maxillary teeth adjacent to single implants in young and mature adults. A retrospective study. J Clin Periodontol 2004;31:1024-8. 9. Jemt T, Ahlberg G, Henriksson K, Bondevik O. Tooth movements adjacent to single-implant restorations after more than 15 years of follow-up. Int J Prosthodont 2007;20:626-32. 10. Thilander B, Odman J, Jemt T. Single implants in the upper incisor region and their relationship to the adjacent teeth. An 8-year follow-up study. Clin Oral Implants Res 1999;10:346-55. 11. Iseri H, Solow B. Continued eruption of maxillary incisors and ﬁrst molars in girls from 9 to 25 years, studied by the implant method. Eur J Orthod 1996;18: 245-56. 12. Bishara SE, Treder JE, Jakobsen JR. Facial and dental changes in adulthood. Am J Orthod Dentofacial Orthop 1994;106:175-86. 13. Pecora NG, Baccetti T, McNamara JA Jr. The aging craniofacial complex: a longitudinal cephalometric study from late adolescence to late adulthood. Am J Orthod Dentofacial Orthop 2008;134:496-505. 14. Stenvik A, Zachrisson BU. Orthodontic closure and transplantation in the treatment of missing anterior teeth. An overview. Endod Dent Traumatol 1993;9:45-52. 15. Zitzmann NU, Krastl G, Hecker H, Walter C, Waltimo T, Weiger R. Strategic considerations in treatment planning: deciding when to treat, extract or replace a questionable tooth. J Prosthet Dent 2010;104:80-91. 16. Zachrisson BU, Stenvik A. Single implants-optimal therapy for missing lateral incisors? Am J Orthod Dentofacial Orthop 2004;126:A13-5.
17. Kern M, Sasse M. Ten-year survival of anterior all-ceramic resin-bonded ﬁxed dental prostheses. J Adhes Dent 2011;13:407-10. 18. Zitzmann NU, Scherrer S, Ozcan M, Bühler J. R W, Krastl G. Resin-bonded restorations: A strategy for managing anterior tooth loss in adolescence. J Prosthet Dent 2015. http://dx.doi.org/10.1016/j.prosdent.2014.09.028. 19. Toscano N, Sabol J, Holtzclaw D, Scott T. Implant repositioning by segmental osteotomy: a case series and review. Int J Periodontics Restorative Dent 2011;31:e102-8. 20. Burk JL Jr, Provencher RF Jr, McKean TW. Small segmental and unitooth ostectomies to correct dentoalveolar deformities. J Oral Surg 1977;35:453-60. 21. Epker BN, Paulus PJ. Surgical-orthodontic correction of adult malocclusions: single-tooth dento-osseous osteotomies. Am J Orthod 1978;74:551-63. 22. Poggio CE, Salvato A. Implant repositioning for esthetic reasons: a clinical report. J Prosthet Dent 2001;86:126-9. 23. Jensen OT, Cockrell R, Kuhike L, Reed C. Anterior maxillary alveolar distraction osteogenesis: a prospective 5-year clinical study. Int J Oral Maxillofac Implants 2002;17:52-68. 24. Oduncuoglu BF, Alaaddinoglu EE, Oguz Y, Uckan S, Erkut S. Repositioning a prosthetically unfavorable implant by vertical distraction osteogenesis. J Oral Maxillofac Surg 2011;69:1628-32. 25. Watzek G, Zechner W, Crismani A, Zauza K. A distraction abutment system for 3-dimensional distraction osteogenesis of the alveolar process: technical note. Int J Oral Maxillofac Implants 2000;15:731-7. 26. Guerrero CA, Laplana R, Figueredo N, Rojas A. Surgical implant repositioning: a clinical report. Int J Oral Maxillofac Implants 1999;14:48-54. 27. Kofod T, Wurtz V, Melsen B. Treatment of an ankylosed central incisor by single tooth dento-osseous osteotomy and a simple distraction device. Am J Orthod Dentofacial Orthop 2005;127:72-80. Corresponding author: Dr Nicola U. Zitzmann Dental School, Hebelstrasse 3 CH-4056 Basel SWITZERLAND Email: [email protected]
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Noteworthy Abstracts of the Current Literature Fracture resistance of three porcelain-layered CAD/CAM zirconia frame designs Ferrari M, Giovannetti A, Carrabba M, Bonadeo G, Rengo C, Monticelli F, Vichi A Dent Mater 2014;30:e163-8 Objectives. Chipping is the most frequent clinical failure of zirconia crowns. Causes of chipping have not been completely understood and different possible reasons have been considered. The study was aimed at evaluating the fracture resistance of 3 different CAD/CAM zirconia frame designs veneered with porcelain. Methods. Thirty extracted sound premolars were divided into 3 groups (n=10). Chamfer preparations were performed, impressions were taken. Three zirconia frame designs (Aadva, GC) were realized: reproduction of the abutment contour (ﬂat design, FD); wax-up as for porcelain-fused-to-metal crowns (PFM); anatomically guided, designed to keep constant the thickness of the overlying porcelain veneering (AG). Porcelain veneering was made with pressure layering technique (Initial Zr, GC). Crowns were cemented utilizing a self-adhesive resin cement (G-Cem, GC). After a 24-h water storage at 37 C, using a universal testing machine (1 mm crosshead speed), crowned teeth were loaded in the central fossa in a direction parallel to the longitudinal axis of the tooth. Load at fracture was recorded in Newtons (N). Digital photographs of the specimens were taken in order to assess failure patterns. Between-group differences in fracture strength were statistically analyzed (One-Way Analysis of Variance, Tukey test, p