The International Journal of Periodontics & Restorative Dentistry

The International Journal of Periodontics & Restorative Dentistry

27 Flapless Implant Surgery in the Esthetic Region: Advantages and Precautions Tae-Ju Oh, DDS, MS 1 /Jeffrey Shotwell, DDS, MS 2 Edward Billy, DMD 3 /Ho-Young Byun, DDS, PhD 4 Hom-Lay Wang, DDS, MSD 5 Because osseointegration is now considered highly predictable, the current trend is to develop techniques that can provide function, esthetics, and comfort with a minimally invasive surgical approach. To achieve those goals, flapless implant surgery using a tissue punch technique has been suggested. This paper presents two clinical cases of single-tooth implants placed in the esthetic region (anterior maxilla), which illustrate systematic approaches to flapless implant surgery for immediate and delayed loading protocol. For both cases, a tissue punch technique using a surgical guide fabricated with the aid of a radiographic stent was performed to provide access for implant site preparation and placement. The implants were loaded either immediately or 4 months after implant placement. With the planned flapless surgical technique, reduced operative time, accelerated postsurgical healing, and increased patient comfort and satisfaction were achieved. This paper also describes precautions of the flapless implant surgery in case selection, surgical techniques, and prosthodontic protocol. In conclusion, appropriate case selection and well-tailored surgical guides with sound surgical and prosthodontic protocols are considered to be the key elements in the success of flapless implant surgery. (Int J Periodontics Restorative Dent 2007;27:27 33.) 1 Clinical Assistant Professor, Department of Periodontics and Oral Medicine, School of Dentistry, University of Michigan at Ann Arbor. 2 Associate Professor, Division of Prosthodontics, Department of Biologic and Materials Science, School of Dentistry, University of Michigan at Ann Arbor. 3 Clinical Professor, Division of Prosthodontics, Department of Biologic and Materials Science, School of Dentistry, University of Michigan at Ann Arbor. 4 Graduate Student, Department of Periodontics and Oral Medicine, School of Dentistry, University of Michigan at Ann Arbor. 5 Professor and Director of Graduate Periodontics, Department of Periodontics and Oral Medicine, School of Dentistry, University of Michigan at Ann Arbor. Correspondence to: Dr Hom-Lay Wang, Department of Periodontics and Oral Medicine, University of Michigan School of Dentistry, 1011 North University Avenue, Ann Arbor, MI 48109-1078; fax: +734-936-0374; e-mail: homlay@umich.edu. Dental implant therapy has been used increasingly frequently for the rehabilitation of missing dentition, replacing conventional therapies in the areas of complete and partial edentulism as well as single-tooth anodontia. 1 5 Originally, the two-stage surgical approach using submerged implants was advocated with the concept that a healing period of at least 3 to 4 months should be allowed to provide a load-free environment and undisturbed healing for successful osseointegration. 6 However, implant therapy utilizing the one-stage surgical protocol (nonsubmerged implants) has also been available, and its successful use has been proven comparable to the two-stage surgical approach. 7,8 With the high predictability of osseointegration, the current trend is geared toward developing methods to enhance patient function, esthetics, and comfort. In implant dentistry, a waiting period to receive implant prosthetics remains a concern for both patient and clinician because of increased anxiety and inconvenience. 9,10 Moreover, esthetic problems persist until the delivery of the definitive restoration when replacing missing teeth in the maxillary anterior Volume 27, Number 1, 2007

28 region, where esthetics is highly demanding. Along with continuous improvements in implant materials, designs (macrostructures and microstructures), and surface treatment techniques, clinical usage of immediate implant loading has been adopted in implant therapeutics, thus providing patients with enhanced function, esthetics, and comfort. The safety and effectiveness of the immediate loading concept have been demonstrated in a number of clinical trials, in both the edentulous mandible (using bilaterally splinted prosthetic designs 10 12 ) and in single-tooth implants. 5,13,14 The establishment of a periimplant soft tissue contour with intact papillae and gingival margins is a major esthetic concern, particularly for patients who display the soft tissue during function, such as smiling or speaking. 15,16 Previous studies have demonstrated that flap reflection often results in gingival recession and bone resorption around natural teeth. 17,18 To minimize the possibility of postoperative peri-implant tissue loss and to overcome the challenge of soft tissue management during or after surgery, the concept of flapless implant surgery has been introduced and clinically applied to both delayed and immediate loading cases. 19 21 This paper presents two clinical cases of single-tooth implants in the esthetic region in which systematic approaches to flapless implant surgery using immediate or delayed loading protocol are described. Both patients were treated at the Graduate Periodontics Clinic at the University of Michigan at Ann Arbor. Patient 1 A 40-year-old, healthy Caucasian woman presented with a missing maxillary right lateral incisor and wished to restore the missing tooth with an implant-supported crown. The patient had a history of smoking a pack of cigarettes a day for 20 years but was otherwise healthy. The initial examination revealed that the width of the keratinized tissue on the edentulous area was sufficient, and adequate ridge width (7 mm), mesiodistal distance (8 mm), and bone height were available for placement of a standard endosseous dental implant (Fig 1a). Prior to implant surgery, preliminary impressions and cast fabrication were carried out, a surgical stent was made, and a periapical radiograph using Rinn XLP devices was obtained at the implant area with a radiographic reference on the surgical stent to verify the direction of future implant drilling (Fig 1b). Under local anesthesia with 2% lidocaine (1:100,000 epinephrine), the center of the implant site was marked on the soft tissue, with guidance by the surgical stent, and the soft tissue was punched with a 4-mm tissue punch (Zimmer Dental) (Figs 1c and 1d). Immediately after the tissue punch, the soft tissue thickness was measured to provide the surgeon and prosthodontist with references, including the location of the crestal bone and emergence profile for implant placement and crown restoration, respectively. A sequential (with drills 2.3, 2.8, and 3.4 mm in diameter), atraumatic implant osteotomy was performed under copious saline irrigation using size-customized surgical guides, followed by placement of a root-form endosseous dental implant (Tapered Screw-Vent MTX implant, Zimmer Dental), 3.7 mm in diameter and 12 mm in length (Fig 1e). After implant placement, an index impression was taken with a clear, lightcuring acrylic resin (Triad Gel, Dentsply) for the fabrication of the definitive crown, which would be placed 4 months postimplantation (Fig 1f). The index was disconnected from the implant and transferred to the cast using an implant analog, and a metalceramic crown was fabricated in a laboratory. Following the index impression, the implant mount was replaced with a healing abutment (5 mm in height), which was flared to develop an esthetic soft tissue emergence profile (Fig 1g). The patient was instructed to perform cold packing on the surgical area extraorally on the day of surgery, and ibuprofen (600 mg every 4 to 6 hours for 2 days) and antibiotics (amoxicillin 500 mg three times daily for 7 days) were prescribed. Postoperative bleeding and swelling were unremarkable, and patient satisfaction was reported as excellent, both immediately after surgery and 1 week later. After 4 months of healing, the healing abutment was removed, the definitive abutment (Hex-Lock abutment, Zimmer Dental) was torqued to the implant with 30 Ncm, and the implant was loaded with the definitive crown, which had been fabricated in a laboratory using the implant-level index. A periapical radiograph using Rinn XLP devices was obtained after abutment connection and crown cementation to ensure intimate connection between the implant, abutment, and crown. The International Journal of Periodontics & Restorative Dentistry

29 Fig 1a (left) Patient 1. The maxillary right lateral incisor was missing, and a singleimplant supported restoration was indicated. Fig 1b (right) Periapical radiograph. A radiographic stent was used to ensure proper angulation of the surgical guide. Fig 1c (left) The soft tissue was marked with guidance by the surgical stent. The clinician attempted to locate the mark at the center of the implant to be placed. Fig 1d (right) The soft tissue was pierced with a 4-mm tissue punch. Fig 1e (left) Implant site preparation was performed using surgical guides made for different sizes of implant drills (2.3, 2.8, and 3.4 mm). Fig 1f (right) Immediately after implant placement with a mount in place, an implant-level index impression was taken. Note the nontraumatized soft tissues around the surgical area. Fig 1g A flared healing abutment (5 mm in height) was connected to the implant to develop a good emergence profile. Fig 1h Clinical photograph taken 6 months after placement of the definitive crown. Fig 1i Periapical radiograph obtained at 6 months after loading. Volume 27, Number 1, 2007

30 There was no change in soft tissue profiles at the implant site and adjacent teeth from the implant surgery, and the tissue levels remained stable and esthetically pleasing at the 6-month follow-up (Figs 1h and 1i). Patient 2 A 39-year-old Hispanic man presented to the clinic with a missing maxillary left second premolar. His medical history was unremarkable, with no history of smoking. The width of the edentulous ridge and the mesiodistal space were sufficient to receive a 3.7-mm endosseous dental implant. There was 2 mm of gingival recession at both of the adjacent teeth (first premolar and first molar); however, the amount of keratinized tissue at the implant site was adequate to perform flapless implant surgery. A tissue punch was made for a flapless surgery using the same protocol described for patient 1. After each implant osteotomy, the direction of preparation was ensured by positioning a guide pin and the surgical guide. Following implant osteotomy, which was guided by surgical stents customized to each implant drill, an endosseous root-form implant (Tapered Screw-Vent MTX implant), 3.7 mm in diameter and 10 mm in length, was placed. As for patient 1, an implant-level index impression was taken using clear, light-curing acrylic resin (Triad Gel) (Fig 2a) for the fabrication of the definitive crown restoration. At chairside, a provisional crown was made on a Hex-Lock plastic provisional abutment, which was handtorqued onto the implant, thus providing the patient with a restoration immediately after implant placement (Fig 2b). Implant primary stability was tested and confirmed by handtorquing the provisional abutment. (If implant stability is not detected at this time, the immediate loading protocol should not be used. Instead, about 4 months of healing time should be allowed for bone maturation and osseointegration.) Any heavy contacts with the provisional crown in centric occlusion were eliminated, and no contacts were provided during protrusive and lateral excursions. Ibuprofen (600 mg every 4 to 6 hours for 2 days) and amoxicillin (500 mg three times daily for 7 days) were prescribed to control postoperative pain and to prevent postoperative infection, respectively. The patient returned to the clinic 10 days postimplantation and received the definitive metal-ceramic crown, which had been fabricated in a laboratory using the index. Heavy contacts were avoided on the implant crown in centric occlusion and during excursive movements. Abutment connection and crown cementation were verified with a standardized periapical radiograph. Healing was uneventful, with no signs of postsurgical complications, and the patient reported minimal discomfort postsurgically. At 1 year, the soft tissue appeared healthy and esthetically pleasing, and no notable bone loss was observed (Figs 2c and 2d). The International Journal of Periodontics & Restorative Dentistry

31 Fig 2a (left) Patient 2. After a tissue punch, sequential implant osteotomy, and implant placement following the same protocol used for patient 1, an implant-level index impression was made using a clear, light-curing acrylic resin. Fig 2b (right) The implant was immediately provisionalized with an acrylic resin crown. Fig 2c (left) At 1 year, no soft tissue recession was noted around the implant. The interdental papillae appeared to fill more of the embrasure spaces than at baseline (compare to Fig 2b). Fig 2d (right) Periapical radiograph at 1 year shows minimal crestal bone loss around the implant. Discussion The present report demonstrated successful use of flapless implant surgery for both immediate and delayed loading protocols. Advantages of the flapless implant surgery, shown in the present cases, included less traumatic surgery and decreased operative time, which resulted in accelerated postsurgical healing, fewer postoperative complications, and increased patient comfort and satisfaction. Especially with the immediate-loading protocol, the advantages were more pronounced because of the absence of a waiting period before prosthetic restoration. Another advantage of the flapless implant surgery was in preservation of soft tissue profiles, including the gingival margins of the adjacent teeth and the interdental papillae. This is attributed to the avoidance of flap reflection, which might cause postsurgical bone resorption and soft tissue recession, as reported in the literature. 17,18 The feasibility of flapless implant surgery with immediate loading 19,21 or with delayed loading 20,22,23 has been demonstrated. However, prerequisites for the flapless implant surgery have also been reported; these include sufficient bone width and height, adequate keratinized soft tissue, and an absence of significant tissue undercuts. 19,20,23 First, sufficient amounts of available bone and keratinized tissue are necessary because direct visualization of bone topography is limited and sacrifice of some keratinized tissue, although minimal, is inevitable in this particular technique. For example, required bone volume for the placement of a standard endosseous root-form implant for the flapless implant surgery would be 7 mm in ridge width, 7 mm in mesiodistal distance, and 10 mm of bone height. In particular, patients with significant tissue undercut should be excluded to prevent tissue dehiscence or fenestration. In the authors opinion, the remaining buccal bone thickness after implant placement should be at least 2.0 mm to minimize postsurgical resorption. This is in agreement with the critical facial bone thickness of 1.8 mm proposed by Spray et al. 24 The critical facial bone thickness must be carefully analyzed when surgical stents are constructed. For the present patients, presurgical radiographs with a radiographic marker were used to evaluate the available bone height and mesiodistal direction of future implant drilling. Computerized tomography or computer imaging software such as Volume 27, Number 1, 2007

32 SimPlant (Materialize) may help increase the precision of surgical templates in guiding the direction of implant drilling. 25 Although debatable, the presence of peri-implant keratinized tissue is regarded beneficial, especially for the longevity of roughsurfaced implants. 26,27 An adequate amount (ie, more than 2 mm) of keratinized tissue must remain on the facial aspect of the implant site after tissue punch. If the soft tissue is insufficient or not expected to be esthetically pleasing after the flapless surgery, soft tissue grafting procedures or papilla regeneration techniques should be considered. In addition to the factors described previously for case selection, precautions should be taken during surgical and prosthodontic procedures. Because of the lack of visibility of hard tissue contours in the flap, it is extremely crucial during implant site preparation to place implant drills against surgical stents using the full length of the apicocoronal drill orientation. Incorrect angulation of implant drills can cause perforation of the cortical plates, usually on the buccal aspect, resulting in dehiscence or fenestration. Although not presented here, perforation of the buccal plate is generally detected by palpation or by observation of implant threads through the soft tissue. With regard to immediate loading, primary stability should be confirmed with hand-torquing of the provisional abutment. If any movement is noted during hand-torquing, a delayed loading protocol should be considered. These cases demonstrate a successful usage of the flapless implant surgery for both delayed and immediate loading cases. Appropriate case evaluation/selection, meticulous planning with well-constructed surgical guides tailored to the specific implant site, and systematic surgical and prosthodontic protocols are considered to be crucial to the success of flapless implant surgery for singletooth implants. Acknowledgments The authors would like to thank Zimmer Dental for their material support. This study was partially supported by a grant from the Periodontal Graduate Student Research Fund, University of Michigan. References 1. Adell R, Lekholm U, Rockler B, Brånemark P-I. A 15-year study of osseointegrated implants in the treatment of the edentulous jaw. Int J Oral Surg 1981;10:387 416. 2. Brånemark P-I, Hansson BO, Adell R, et al. Osseointegrated implants in the treatment of the edentulous jaw. Experience from a 10-year period. Scand J Plast Reconstr Surg Suppl 1977;16:1 132. 3. van Steenberghe D. A retrospective multicenter evaluation of the survival rate of osseointegrated fixtures supporting fixed partial prostheses in the treatment of partial edentulism. J Prosthet Dent 1989;61:217 223. 4. Palmer RM, Palmer PJ, Smith BJ. A 5-year prospective study of Astra single tooth implants. Clin Oral Implants Res 2000;11:179 182. 5. Andersen E, Haanæs HR, Knutsen BM. Immediate loading of single-tooth ITI implants in the anterior maxilla: A prospective 5-year pilot study. Clin Oral Implants Res 2002;13:281 287. The International Journal of Periodontics & Restorative Dentistry

33 6. Albrektsson T, Brånemark P-I, Hansson HA, Lindstrom J. Osseointegrated titanium implants. Requirements for ensuring a long-lasting, direct bone-to-implant anchorage in man. Acta Orthop Scand 1981;52:155 170. 7. Buser D, Mericske-Stern R, Bernard JP, et al. Long term evaluation of non-submerged ITI implants. Part I: 8-year life table analysis of a prospective multi-center study with 2359 implants. Clin Oral Implants Res 1997;8:161 172. 8. Weber HP, Buser D, Fiorellini JP, Williams RC. Radiographic evaluation of crestal bone levels adjacent to nonsubmerged titanium implants. Clin Oral Implants Res 1992;3:181 188. 9. Salama H, Rose LF, Salama M, Betts NJ. Immediate loading of bilaterally splinted titanium root-form implants in fixed prosthodontics A technique reexamined: two case reports. Int J Periodontics Restorative Dent 1995;15:344 361. 10. Schnitman PA, Wohrle PS, Rubenstein JE, DaSilva JD, Wang NH. Ten-year results for Brånemark implants immediately loaded with fixed prostheses at implant placement. Int J Oral Maxillofac Implants 1997;12:495 503. 11. Testori T, Szmukler-Moncler S, Francetti L, et al. Immediate loading of Osseotite implants: A case report and histologic analysis after 4 months of occlusal loading. Int J Periodontics Restorative Dent 2001; 21:451 459. 12. Chiapasco M, Abati S, Romeo E, Vogel G. Implant-retained mandibular overdentures with Brånemark System MKII implants: A prospective comparative study between delayed and immediate loading. Int J Oral Maxillofac Implants 2001;16:537 546. 13. Cooper L, Felton DA, Kugelberg CF, et al. A multicenter 12-month evaluation of single-tooth implants restored 3 weeks after 1-stage surgery. Int J Oral Maxillofac Implants 2001;16:182 192. 14. Lorenzoni M, Pertl C, Zhang K, Wimmer G, Wegscheider WA. Immediate loading of single-tooth implants in the anterior maxilla. Preliminary results after one year. Clin Oral Implants Res 2003;14:180 187. 15. Choquet V, Hermans M, Adriaenssens P, Daelemans P, Tarnow DP, Malevez C. Clinical and radiographic evaluation of the papilla level adjacent to single-tooth dental implants. A retrospective study in the maxillary anterior region. J Periodontol 2001;72:1364 1371. 16. Grossberg DE. Interimplant papilla reconstruction: Assessment of soft tissue changes and results of 12 consecutive cases. J Periodontol 2001;72:958 962. 17. Ramfjord SP, Costich ER. Healing after exposure of periosteum on the alveolar process. J Periodontol 1968;38:199 207. 18. Wood DL, Hoag PM, Donnenfeld OW, Rosenfeld LD. Alveolar crest reduction following full and partial thickness flaps. J Periodontol 1972;42:141 144. 19. Hahn J. Single-stage, immediate loading, and flapless surgery. J Oral Implantol 2000;26:193 198. 20. Campelo LD, Camara JR. Flapless implant surgery: A 10-year clinical retrospective analysis. Int J Oral Maxillofac Implants 2002;17:271 276. 21. Rocci A, Martignoni M, Gottlow J. Immediate loading in the maxilla using flapless surgery, implants placed in predetermined positions, and prefabricated provisional restorations: A retrospective 3- year clinical study. Clin Implant Dent Relat Res 2003;5(suppl 1):29 36. 22. al-ansari BH, Morris RR. Placement of dental implants without flap surgery: A clinical report. Int J Oral Maxillofac Implants 1998;13:861 865. 23. Kan JYK, Rungcharassaeng K, Ojano M, Goodacre CJ. Flapless anterior implant surgery: A surgical and prosthodontic rationale. Pract Periodontics Aesthet Dent 2000;12:467 474. 24. Spray JR, Black CG, Morris HF, Ochi S. The influence of bone thickness on facial marginal bone response: Stage 1 placement through stage 2 uncovering. Ann Periodontol 2000;5:119 128. 25. Klein M, Abrams M. Computer-guided surgery utilizing a computer-milled surgical template. Pract Periodontics Aesthet Dent 2001;13:165 169. 26. Block MS, Kent JN. Factors associated with soft- and hard-tissue compromise of endosseous implants. Int J Oral Maxillofac Surg 1990;48:1152 1160. 27. Warrer K, Buser D, Lang NP, Karring T. Plaque-induced peri-implantitis in the presence of absence of keratinized mucosa. An experimental study in monkeys. Clin Oral Implants Res 1995;6: 131 138. Volume 27, Number 1, 2007