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Sinus floor lift and simultaneous implant placement: A retrospective evaluation of implant success rate
Indian Journal of Dentistry 2012 JulyeSeptember Volume 3, Number 3; pp. 132e138
Original Article
Sinus floor lift and simultaneous implant placement: A retrospective evaluation of implant success rate M. Rapania,*,c, C. Rapanib,c
ABSTRACT Aim: The purpose of the present retrospective investigation was to evaluate the survivability and success of implants placed simultaneously during direct sinus lifts with allograft forms of bone with a follow up from one to four years. Materials and methods: 110 patients were included in this study. A radiological evaluation was done before the surgical treatment by a OPG and intraoral radiographs. A cone beam CT was done when it was indicated. All patients received a sinus lift surgery with a contemporary implant placement. Success and failure rate was recorded in a follow up from one year to four years since the implant placement. Results: Maxillary sinus surgery is a reliable and predictable treatment option for the prosthetic rehabilitation of the atrophic maxilla. A correct surgery planning is a way to avoid post-operative complications and to an adequate prosthetic rehabilitation. Implant success, in this retrospective study is 97.7% at 1 year follow up and 96.9% at 2 years follow up. Prosthetic success at a 4 year follow up (115 prosthetic treatment in 108 patients) has been 98%. Conclusions: A complete pre surgical planning and careful patient selections can produce a predictable results for implant prosthesis treatment. Keywords: Sinus lift, Sinus floor elevation, Implants, Implant success rate, Complications
INTRODUCTION The placement of endosseous implants in edentulous areas of the jaw is frequently limited by inadequate bone volume of the residual ridge.1 Ridge resorption and sinus pneumatization in the posterior maxilla, compounded with a poor quality of bone, can compromise implant rehabilitation of the patient.2 To increase the amount of bone in the maxilla, the sinus floor elevation procedure, or subantral augmentation, has been developed. This procedure involves placing bone graft material in the maxillary sinus to increase the height and width of the alveolus.6e16
a
Maxillary sinus lift is an established surgical procedure indicated to improve posterior maxillary bone height when enough bone is not present for the installation of endosseous implants. Although autogenous bone graft is still considered the criterion standard graft material for several reasons published elsewhere, natural and synthetic biomaterials are being used for this purpose, with variable results.16,17,36 This issue is still debated in the literature as there are still several schools of thought on this subject. Sinus lift procedures for an implantprosthetic rehabilitation are nowadays considered a predictable treatment and a safe technique for prosthetic works.22e28 Nowadays surgical techniques and GBR procedures are predictable, because standard procedures allows to have an
Licence en médecine dentaire, Doctor of Dental Science, Dental technician, bDoctor of Medicine and Surgery, General and Oral Surgery Specialist, Chieti, Italy. * Corresponding author. Via F. Salomone 83; 66100 Chieti (Italy), email: [email protected] Received: 18.11.2011; Accepted: 23.5.2012 c Private practice dental office “Studio Rapani”. Ó 2012 Indian Journal of Dentistry. All rights reserved. http://dx.doi.org/10.1016/j.ijd.2012.05.003
Sinus floor lift and simultaneous implant placement
Original Article
important bone increment and a good bone consistence to assure a primary stability of the implant also when they are in contact with the sinusal region (Brånemark e Albrektsson).18 Tatum e Lebowitz31 presented in ’70, the “inverted lateral window” technique and they implemented a bone deficit with an autologous graft. Based on numerous reports of bone grafts in the maxillary sinus and the corresponding loading times after implant placement, it was found that the cases with 5e6 months healing periods were most abundant. Balshi16 reported that it was adequate to allow 8e10 months of healing when bone replacement graft materials, such as BioOss, were used alone, and in the cases that used a mixture of autogenous bones and BioOss at a 1:1 ratio, the healing period could be shortened to 6e8 months.16 It has been reported that good results could be obtained if the patients who could achieve sufficient primary stability of the implant are selected appropriately, regardless of the residual bone amount and even if implant placement is performed simultaneously.20 Kim et al21 showed that between the cases with 4 months and 6 months loading times after simultaneous maxillary sinus bone graft and implant placement, the short-term prognosis was not greatly different. If cases are chosen appropriately to achieve primary stability, even in the cases in which bone grafts and implant placements are performed simultaneously and loading is placed at the time point of 4 months after placement, good results can be obtained (Table 1). These studies of simultaneous placement have all shown excellent short-term and long-term implant survival rates ranging from 100% in the short-term studies (1 year) to 94.2% in the long-term (9- to 10year studies), regardless of the initial bone height available. The histological findings have also been favorable and have confirmed the bone turnover of the materials used (graft replacement) with time. Implant therapy is being included in treatment plans more routinely because of its high success rates. The purpose of the present retrospective investigation was to evaluate the survivability and success of endosseous implants, and relative prosthetic survival, at one to four year after loading. Table 1 Patients inclused in the study and implant’s distributions. Patients: M F Total
52 68 120
Implants
Tixos
Conic
Cylindrical
152 146 298
98 89 187
32 28 60
31 20 51
133
MATERIALS AND METHOD Study design This study was conducted retrospectively on patients who underwent sinus bone grafts using a lateral approach and simultaneous implant placements performed by a single oral surgeon from January 2006 to December 2007. The present retrospective analysis included 120 patients (52 woman and 68 male) between 24 and 70 years who needed prosthetic rehabilitation in posterior maxillary area. 85% (253) of implants were placed simultaneously and only 15% were loaded after 8 months. All patients were given a fixed implant-supported prosthesis.
Inclusion criteria Patients without general health complications or any surgical contra-indication; patients with crestal height was 5 mm or less; presence of posterior uni or bilateral edentulous areas of the superior jaw and where a fixed implantsupported prosthesis was desired by the patient. Good dental hygiene was recorded and consultation with a Dental Hygienist was done; only non smokers or patients who smoked less than 10 cig/day were included. The surgical and prosthetic parts were the last step of the complete dental treatments. All the patients were informed about the possibility of some post surgical complications after confirming absence of any sinus pathologies and if a doubt was present patients where sent to a otolaryngologist visit. Patients only with the specialist’s confirmations were included in this study (Fig. 1).
Surgical Procedure Radiological evaluation was made by an OPG X ray evaluation, with intraoral radiography and, when necessary, with a Cone Beam technique. All the patients were treated with an antibiotic treatment using Amoxycillin and Clavulanate Pottassium (2 gram 1 h before the surgery and 1 gr each 12 h during the following 6 days). Patient was asked to rinse with 0.2% chlorhexidine mouthwash prior to surgical procedure. Surgery was performed under a local anesthesia by ArticaineÒ infiltration (Ubistesin 4% e Espe Dental AG Seefeld, Germany) with adrenaline 1:100.000. After a crestal and bi-lateral oblique releasing incision, surgical areas were exposed sufficiently by the full-thickness mucoperiosteal flap elevation. After exposure of the alveolar ridge, measurements were taken to assess the effective bony width.
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Fig. 1 (a) Pre surgical radiological evaluation, (b) post surgical follow up, in a different case, (c) post definitive loading radiograph (after 1 year follow up).
The vertical level of the residual crest was taken directly in the patient’s mouth with the aid of two periodontal probes. The reference line used was the one connecting the cusps of the 2 teeth adjacent to the bone defect. After evaluation of the bone defects, a bony window was designed on the lateral wall of the sinus and was removed or elevated towards the medial wall. The entry into the maxillary sinus was performed via the lateral access window (modified Caldwell-Luc technique), or a less invasive approach through the crest of the alveolar ridge. The window approach was made with a burr on a piezoelectric unit (Piezotome e Satelec e Bordeux). In both cases, the Schneiderian membrane, covering the bony sinus, was gently separated from the sinus floor and elevated to contain graft material that is placed inferiorly. Careful sinus membrane elevation was performed and the presence or absence of perforation was evaluated. Ideal implant position was marked with a round burr. Using a surgical stent, the initial and serial drillings of the implant placement area were performed using implant’s burr sequence on an implant’s motors (Implacenter, Satelec, Bordeaux). The final drilling was performed with a counter sink when the bone density was really high. Implants used in this study are 187 Tixos (Leader, Novaxa-Italy); 51 cylindrical type (Leader, Novaxa e Italy) and 72 conic type (Leader, Novaxa-Italy). As regenerative materials authors used a resorbable membrane that was adapted on the regenerative tissues to protect it from the epithelial ingrowth and to allow the blood to refill the surgical site and make new bone. The membrane used in this study is pure collagen that is produced from bovine pericardium (Lyoplant Braun). A periosteal incision was given to make the flap more elastic and it permitted hermatic closure of the surgical site, by a suture with a 4/0 supramid (Supramid, Braun) for the crest incision and a 6/0 (Supramid, Braun) for lateral oblique releasing incisions.
Sutures were removed after 10 days. In all cases, no postsurgical infection or complications were detected (Fig. 2).
Radiographic data The radiographs (bitewings, periapical, and orthopantomogram for each patient) were taken at the end of the surgery appointment and immediately after the initial functional crown was placed (regardless of whether it was temporary or final) to serve for implant placement control and the baseline radiographic measurements for the sinus grafts and the crestal bone levels at time “zero” of initial loading. All radiographs were taken to ensure they were “diagnostic”. Bitewing radiographs (in which the entire length of the implant was most commonly visible) or OPG were taken again at a minimum of 12e48 months after functional loading of the implant and compared with those at baseline (ie, time of functional crown insertion). This radiographic evaluation, combined with the appropriate clinical criteria as described by Smith and Zarb39 in 1989, have been readily accepted as the reference standard (Fig. 3).
Implant success criteria Authors recorded the following criteria, suggested in international literature: No pain or tenderness on function; No mobility; Overall interproximal radiographic bone loss 2 mm from time of initial implant placement; Interproximal radiographic bone loss than 1.5 mm from the time of crown placement and initial functional loading to 1 year of functional loading; No pathologic peri-implant attachment loss indications (Table 2). Misch et al9 in 2008 explained these criteria which suggested that successful implants were those that did not experience any pain with function, any mobility, any exudate history, or more than 2 mm of radiographic bone loss since the placement date.19
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Original Article
135
Fig. 2 Lateral access to the sinus lift in 3 different patients.
RESULTS This retrospective study was conducted on patients who underwent sinus bone grafts using a lateral approach and simultaneous implant placements performed by a single oral surgery from January 2006 to December 2007. The present analysis included 120 patients (52 woman and 68 male) between 24 and 70 years who needed prosthetic rehabilitation in posterior area. All patients wanted a fixed implant-supported prostheses. A total of 253 implant were placed at time 0 and only 45 were loaded after 8 months. At 6 weeks follow up 6 implants were lost, 3 in a woman 42 years old and 2 in a woman 49 years old. 1 implant was lost in a man 65 years old, 4 weeks after the surgery. In patients with an implant failure, another implant was placed 9 months after the implant removal. On 310 implants placed, 4 implants were lost between the 4th and the 6th weeks. The 292 implants were loaded with a total of 115 prostheses, between temporary or final restorations, and at each recall for the dental hygiene. Authors made a clinical or clinical and radiographical check of the implants. Three implants failed in 2 patients with prosthetic restoration loss.
At the time of the last follow up, the sinus bone graft resorption, crestal bone loss, and soft tissue condition (width of attached gingiva, plaque index, gingival inflammatory index, and probing depth) around the implants between the 3 types were not different. Implant success, in this retrospective study is 97.7% at 1 year follow up and 96.9% at 2 years follow up. Prosthetic success at a 4 year follow up (115 prosthetic treatment in 108 patients) has been 98% (Table 3).
DISCUSSION Generalized atrophy of the alveolar crest is compounded by pneumatization of the maxillary sinus, often rendering only a few millimeters of bone available for implant insertion. Different augmentation procedures have been developed. Sinus floor elevation plays an increasingly important role in oral surgery. Early reports by Tatum1 and Boyne6 described the lateral window technique. Implant therapy is being included in treatment plans more routinely because of its high success rates. Lack of available bone and enlarged sinus cavities are often a major obstacle to the placement of dental implants in the posterior maxilla. To increase the amount of bone in the maxilla, the sinus floor elevation procedure, or subantral augmentation,
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Fig. 3 3 One step sinus lift and implants placements in 3 different cases.
has been developed. This procedure involves placing bone graft material in the maxillary sinus to increase the height and width of the alveolus.3,6e16 Sinus augmentation with simultaneous implant placement has gained popularity and is now commonly used by more clinicians in the appropriate clinical circumstances therefore the decision to place an implant concurrently with sinus elevation surgery is usually determined by the Table 2 Implant’s height and width. Length 3.75 3.75 3.75 4.5 4.5 5 5
Width
Tixos
Conic
Cylindrical
Total
8 10 13 8 10 8 10
5 32 14 0 10 0 0 187
3 4 44 0 0 0 0 51
4 6 50 0 0 0 2 60
12 42 234 0 10 0 0 298
operator’s experience and the amount of residual sinus floor bone height the surgeon is comfortable with.4,5,37,38 Del Fabbro et al29 performed a systematic review of 39 selected studies (out of 252 screened as full text) in which 2046 patients underwent sinus-grafting and received 6913 implants. After a follow up period ranging from 12 to 75 months, an overall survival rate of 92.5% was reported (range, 61.2%e100%). Results were also divided according to the type of grafting materials. Overall, the survival rate of implants was 87.7% with autogenous bone, 94.9% when autogenous bone was mixed with other grafting materials, and 95.9% with non autogenous grafting materials. Results were also reported according to the type of implant surface. Overall, the survival rate was 85.6% for implants with smooth/machined surfaces, and 95.9% for implants with rough surfaces. This issue is still debated in the literature as there are still several schools of thought on this subject. A review of the literature by Chiapasco et al30 selected 57 studies (out of 470 screened as full text) in which 3163 patients were treated with 3947 sinus-grafting
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137
Table 3 Follow up. Implants Implants Implants Implants Total
presents success rate survival failed
Time 0
2 Months follow up
2 Years follow up
3 Years follow up
4 Years follow up
Rate%
298
292 97.9%
306 96.9%
306 96.9
306 96.9
98.7%
6 292
3 289
0 289
0 289
298
procedures and 8781 implants (3760 immediate, 3503 delayed, and 1518 nonspecified). In a longitudinal follow up study by Chiapasco et al.,31 692 patients underwent 952 sinus-grafting procedures (of whom 579 also received concomitant vertical and/or horizontal reconstruction with only grafts) and the placement of 2037 implants. After a mean follow up of 59 months (range, 12e 144 months), an overall survival rate of 95.8% was reported. On the other hand, different studies reported that the prognosis for performing maxillary sinus bone grafts first and placing implants second is good, and the delayed technique can reduce the risk of the infection of grafted bones. In addition, it has been reported that, compared with simultaneous implantation, delayed implantation allowed placement of implants in appropriate positions.33e35 Examining earlier research results on the selection of simultaneous versus delayed placement, it was found that the residual bone amount and the primary implant stability were important factors. Kim et al21 concluded that if cases are chosen appropriately to achieve primary stability, even in the cases in which bone grafts and implant placements are performed simultaneously and loading is placed at the time point of 4 months after placement, good results can be obtained. Chiapasco et al32 explained that the edentulous posterior maxilla may present an extremely wide variety of clinical situations, ranging from mild atrophy and sinus pneumatization to extreme 3-dimensional atrophy. Authors are convinced that every clinica case represents a “unique” situation not only as far as type of atrophy is concerned, but also in terms of other important factors, including post-operative morbidity, a patient’s expectations and compliance, number of surgical procedures needed, rehabilitation times, costs, and esthetic and functional outcome.
CONCLUSIONS On 298 implants the failure rate at 1 year follow up was 97.9%. At 2 years follow up the survival and success rate was 96.9% and a 4 years follow up it is still 96.9%. With all the limits of this retrospective study, made in a private practice with a limited number of patients, in accordance with Kim et al21 authors conclude that a complete pre
surgical planning and a careful patients selections can produce predictable results for implant prosthesis treatment. Prosthetic success at 4 year (115 prosthetic treatment in 108 patients) has been 98%.
REFERENCES 1. Adeyemo WL, Reuther T, Bloch W, et al. Healing of only mandibular bone grafts covered with collagen membrane or bovine bone substitutes: a microscopical and immunohistochemical study in the sheep. Int J Oral Maxillofac Surg. 2008;37:651. 2. Tatum H. Maxillary and sinus implant reconstruction. Dent Clin North Am. 1986;30:613e616. 3. Lee HJ, Choi BH, Jung JH, et al. Maxillary sinus floor augmen-tation using autogenous bone grafts and platelet-enriched fibrin glue with simultaneous implant placement. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2007;103:329. 4. Chen TW, Chang HS, Leung KW, et al. Implant placement immediately after the lateral approach of the trap door window procedure to create a maxillary sinus lift without bone grafting: a 2-year retrospective evaluation of 47 implants in 33 patients. J Oral Maxillofac Surg. 2007;65:2324. 5. Mazor Z, Peleg M, Garg AK, et al. The use of hydroxyapatite bone cement for sinus floor augmentation with simultaneous implant placement in the atrophic maxilla: a report of 10 cases. J Periodontol. 2000;71:1187. 6. Boyne PJ, James RA. Grafting of the maxillary sinus floor with autogenous marrow and bone. J Oral Surg. 1980;38: 613e616. 7. Chen L, Cha J. An 8-year retrospective study: 1,100 patients receiving 1,557 implants using the minimally invasive hydraulic sinus condensing technique. J Periodontol. 2005;76:482e491. 8. Choukroun J, Simonpieri A, Del Corso M, et al. Controlling sys-tematic perioperative anaerobic contamination during sinus-lift procedures by using metronidazole: an innovative approach. Implant Dent. 2008;17:257e270. 9. Guillot P, Colin A, Utada AS, Ajdari A. Stability of a jet in confined pressure-driven biphasic flows at low Reynolds numbers. Phys Rev Lett. 2007;99:104e502. 10. Misch CE. Maxillary sinus augmentation for endosteal implants: organized alter-native treatment plans. Int J Oral. 1987;4:49e58.
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11. Nkenke E, Schlegel A, Schultze-Mosgau S, Neukam FW, Wiltfang J. The endoscopically controlled osteotome sinus floor elevation: a preliminary pro- spective study. Int J Maxillofac Implants. 2002;17:557e566. 12. Peleg M, Garg AK, Mazor Z. Predict-ability of simultaneous implant place-ment in the severely atrophic posterior maxilla: a 9 year longitudinal experience study of 2132 implants placed into 731 human sinus grafts. Int J Oral Maxillofac Implants. 2006;21:94e102. 13. Pikos MA. Maxillary sinus membrane repair: report of a technique for large perforations. Implant Dent. 1999;8:29e34. 14. Reiser G, Rabinovitz Z, Bruno J, Damoulis P, Griffin T. Evaluation of maxillary sinus membrane response following elevation with the crestal osteotome technique in human cadavers. Int J Oral Maxillofac Implants. 2001;16:833e844. 15. Smedberg J, Johansson B, Ekenback J, Wannfors K. Implants and sinus-inlay graft in a 1-stage procedure in severely atrophied maxillae: prosthodontic aspects in a 3-year follow-up study. Int J Oral Maxillofac Implants. 2001;16:668e674. 16. Stricker A, Voss PJ, Gutwald R, Schramm A, Schmelzeisen R. Maxillary sinus floor augmentation with auto-genous bone grafts to enable placement of SLA-surfaced implants: preliminary results after 15e40 months. Clin Oral Implants Res. 2003;14:207e212. 17. Tatum H. Maxillary and sinus implant reconstructions. Dent Clin N Am. 1986;30:207e229. 18. Velich N, Németh Z, Tóth C, Szabó G. Long-term results with different bone substitutes used for sinus floor elevation. J Craniofac Surg. 2004;15:38. 19. Ozyuvaci H, Bilgic B, Fiatli E. Radiologic and histomorphomet- ric evaluation of sinus grafting with alloplastic graft materials. J Periodontol. 2003;74:909. 20. Brånemark PI, Adell R, Albrektsson T, et al. An experimental and clinical study of osseointegrated implants penetrating the nasal cavity and maxillary sinus. J Oral Maxillofac Surg. 1984;42:497e505. 21. Balshi TJ. Sinus augmentation for implant reconstruction. Prosthodontic Insights. 1997;10:1e5. 22. Kim YK, Kim SG, Lee BG. Bone graft and implant. Seoul: Narae; 2007. p. 160e311. 23. Kim YK, et al Comparison of clinical outcomes of sinus bone graft with simultaneous implant placement: 4-month and 6month final prosthetic loading. Oral-Surgery, Oral-Medicine, Oral-Pathology, Oral-Radiology, and Endodontology Volume 111, Number 2 24. Wallace SS, Froum SJ. Effect of maxillary sinus augmentation on the survival of endosseous dental implants: a systematic review. Ann Periodontol. 2003;8:328e343. 25. Del Fabbro M, Testori T, Francetti L, Weinstein R. Systematic review of survival rates for implants placed in the grafted maxillary sinus. Int J Periodontics Restorative Dent. 2004;24:565e577.
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26. Del Fabbro M, Rosano G, Taschieri S. Implant survival rates after maxillary sinus augmentation. Eur J Oral Sci. 2008;116: 497e506. 27. Aghaloo TL, Moy PK. Which hard tissue augmentation techniques are the most successful in furnishing bonysupport for implant placement? Int J Oral Maxillofac Implants. 2007;22(Suppl.):49e70. 28. Pjetursson BE, Tan WC, Zwahlen M, Lang NP. A systematic review of the successof sinus floor elevation and survival of implants inserted in combination with sinus floor elevation. J Clin Periodontol. 2008;35:216e240. 29. Chiapasco M, Casentini P, Zaniboni M. Bone augmentation procedures in implant dentistry. Int J Oral Maxillofac Implants. 2009;24:237e259. 30. Esposito M, Piattelli M, Pistilli R, Pellegrino G, Felice P. Sinus lift with guided bone regeneration or anorganic bovine bone: 1-year post-loading results of a pilot randomised clinical trial. Eur J Oral Implantol. 2010;3:297e305. 31. Del Fabbro M, Testori T, Francetti L, et al. Systematic review of survival rates for implants placed in the grafted maxillary sinus. Int J Periodont Rest Dent. 2004;24:565. 32. Chiapasco M, Zaniboni M, Boisco M. Augmentation procedures for the rehabilitation of deficient edentulous ridges with oral implants. Clin Oral Implant Res. 2006;17(Suppl. 2):136. 33. Chiapasco M, Zaniboni M, Rimondini L. Dentalimplantsplacedin grafted maxillary sinuses: a retrospective analysis of clinical out- come according to the initial clinical situtation and a proposal of defect classification. Clin Oral Implant Res. 2008;19:416. 34. Chiapasco M, Marco Zaniboni. DDSy2009 American Association of oral and Maxillofacial Surgeons. J Oral Maxillofac Surg. 2009;67:867e871. 35. Blomqvist JE, Alberius P, Isaksson S. Sinus inlay bone augmen- tation: comparison of implant positioning after one- or two- staged procedures. J Oral Maxillofac Surg. 1997;55: 804e810. 36. Hall HD, McKenna SJ. Bone graft of the maxillary sinus floor for Branemark implants. Oral Maxillofac Surg Clin North Am. 1991;3:869e875. 37. Kahnberg KE, Ekestubbe A, Gröndahl K, Nilsson P, Hirsch JM. Sinus lifting procedure. I. One-stage surgery with bone transplant and implants. Clin Oral Implants Res. 2001;12:479e487. 38. Tassos Irinakis. Efficacy of injectable demineralized bone matrix as graft material during sinus elevation surgery with simultaneous implant placement in the posterior maxilla: clinical evaluation of 49 sinuses. J Oral Maxillofac Surg. January 2011;69(1):134e141. 39. Smith DE, Zarb GA. Criteria for success of osseointegrated endosseous implants. J Prosthet Dent. 1989;62: 567e572.
Original Article
Sinus floor lift and simultaneous implant placement: A retrospective evaluation of implant success rate M. Rapania,*,c, C. Rapanib,c
ABSTRACT Aim: The purpose of the present retrospective investigation was to evaluate the survivability and success of implants placed simultaneously during direct sinus lifts with allograft forms of bone with a follow up from one to four years. Materials and methods: 110 patients were included in this study. A radiological evaluation was done before the surgical treatment by a OPG and intraoral radiographs. A cone beam CT was done when it was indicated. All patients received a sinus lift surgery with a contemporary implant placement. Success and failure rate was recorded in a follow up from one year to four years since the implant placement. Results: Maxillary sinus surgery is a reliable and predictable treatment option for the prosthetic rehabilitation of the atrophic maxilla. A correct surgery planning is a way to avoid post-operative complications and to an adequate prosthetic rehabilitation. Implant success, in this retrospective study is 97.7% at 1 year follow up and 96.9% at 2 years follow up. Prosthetic success at a 4 year follow up (115 prosthetic treatment in 108 patients) has been 98%. Conclusions: A complete pre surgical planning and careful patient selections can produce a predictable results for implant prosthesis treatment. Keywords: Sinus lift, Sinus floor elevation, Implants, Implant success rate, Complications
INTRODUCTION The placement of endosseous implants in edentulous areas of the jaw is frequently limited by inadequate bone volume of the residual ridge.1 Ridge resorption and sinus pneumatization in the posterior maxilla, compounded with a poor quality of bone, can compromise implant rehabilitation of the patient.2 To increase the amount of bone in the maxilla, the sinus floor elevation procedure, or subantral augmentation, has been developed. This procedure involves placing bone graft material in the maxillary sinus to increase the height and width of the alveolus.6e16
a
Maxillary sinus lift is an established surgical procedure indicated to improve posterior maxillary bone height when enough bone is not present for the installation of endosseous implants. Although autogenous bone graft is still considered the criterion standard graft material for several reasons published elsewhere, natural and synthetic biomaterials are being used for this purpose, with variable results.16,17,36 This issue is still debated in the literature as there are still several schools of thought on this subject. Sinus lift procedures for an implantprosthetic rehabilitation are nowadays considered a predictable treatment and a safe technique for prosthetic works.22e28 Nowadays surgical techniques and GBR procedures are predictable, because standard procedures allows to have an
Licence en médecine dentaire, Doctor of Dental Science, Dental technician, bDoctor of Medicine and Surgery, General and Oral Surgery Specialist, Chieti, Italy. * Corresponding author. Via F. Salomone 83; 66100 Chieti (Italy), email: [email protected] Received: 18.11.2011; Accepted: 23.5.2012 c Private practice dental office “Studio Rapani”. Ó 2012 Indian Journal of Dentistry. All rights reserved. http://dx.doi.org/10.1016/j.ijd.2012.05.003
Sinus floor lift and simultaneous implant placement
Original Article
important bone increment and a good bone consistence to assure a primary stability of the implant also when they are in contact with the sinusal region (Brånemark e Albrektsson).18 Tatum e Lebowitz31 presented in ’70, the “inverted lateral window” technique and they implemented a bone deficit with an autologous graft. Based on numerous reports of bone grafts in the maxillary sinus and the corresponding loading times after implant placement, it was found that the cases with 5e6 months healing periods were most abundant. Balshi16 reported that it was adequate to allow 8e10 months of healing when bone replacement graft materials, such as BioOss, were used alone, and in the cases that used a mixture of autogenous bones and BioOss at a 1:1 ratio, the healing period could be shortened to 6e8 months.16 It has been reported that good results could be obtained if the patients who could achieve sufficient primary stability of the implant are selected appropriately, regardless of the residual bone amount and even if implant placement is performed simultaneously.20 Kim et al21 showed that between the cases with 4 months and 6 months loading times after simultaneous maxillary sinus bone graft and implant placement, the short-term prognosis was not greatly different. If cases are chosen appropriately to achieve primary stability, even in the cases in which bone grafts and implant placements are performed simultaneously and loading is placed at the time point of 4 months after placement, good results can be obtained (Table 1). These studies of simultaneous placement have all shown excellent short-term and long-term implant survival rates ranging from 100% in the short-term studies (1 year) to 94.2% in the long-term (9- to 10year studies), regardless of the initial bone height available. The histological findings have also been favorable and have confirmed the bone turnover of the materials used (graft replacement) with time. Implant therapy is being included in treatment plans more routinely because of its high success rates. The purpose of the present retrospective investigation was to evaluate the survivability and success of endosseous implants, and relative prosthetic survival, at one to four year after loading. Table 1 Patients inclused in the study and implant’s distributions. Patients: M F Total
52 68 120
Implants
Tixos
Conic
Cylindrical
152 146 298
98 89 187
32 28 60
31 20 51
133
MATERIALS AND METHOD Study design This study was conducted retrospectively on patients who underwent sinus bone grafts using a lateral approach and simultaneous implant placements performed by a single oral surgeon from January 2006 to December 2007. The present retrospective analysis included 120 patients (52 woman and 68 male) between 24 and 70 years who needed prosthetic rehabilitation in posterior maxillary area. 85% (253) of implants were placed simultaneously and only 15% were loaded after 8 months. All patients were given a fixed implant-supported prosthesis.
Inclusion criteria Patients without general health complications or any surgical contra-indication; patients with crestal height was 5 mm or less; presence of posterior uni or bilateral edentulous areas of the superior jaw and where a fixed implantsupported prosthesis was desired by the patient. Good dental hygiene was recorded and consultation with a Dental Hygienist was done; only non smokers or patients who smoked less than 10 cig/day were included. The surgical and prosthetic parts were the last step of the complete dental treatments. All the patients were informed about the possibility of some post surgical complications after confirming absence of any sinus pathologies and if a doubt was present patients where sent to a otolaryngologist visit. Patients only with the specialist’s confirmations were included in this study (Fig. 1).
Surgical Procedure Radiological evaluation was made by an OPG X ray evaluation, with intraoral radiography and, when necessary, with a Cone Beam technique. All the patients were treated with an antibiotic treatment using Amoxycillin and Clavulanate Pottassium (2 gram 1 h before the surgery and 1 gr each 12 h during the following 6 days). Patient was asked to rinse with 0.2% chlorhexidine mouthwash prior to surgical procedure. Surgery was performed under a local anesthesia by ArticaineÒ infiltration (Ubistesin 4% e Espe Dental AG Seefeld, Germany) with adrenaline 1:100.000. After a crestal and bi-lateral oblique releasing incision, surgical areas were exposed sufficiently by the full-thickness mucoperiosteal flap elevation. After exposure of the alveolar ridge, measurements were taken to assess the effective bony width.
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Fig. 1 (a) Pre surgical radiological evaluation, (b) post surgical follow up, in a different case, (c) post definitive loading radiograph (after 1 year follow up).
The vertical level of the residual crest was taken directly in the patient’s mouth with the aid of two periodontal probes. The reference line used was the one connecting the cusps of the 2 teeth adjacent to the bone defect. After evaluation of the bone defects, a bony window was designed on the lateral wall of the sinus and was removed or elevated towards the medial wall. The entry into the maxillary sinus was performed via the lateral access window (modified Caldwell-Luc technique), or a less invasive approach through the crest of the alveolar ridge. The window approach was made with a burr on a piezoelectric unit (Piezotome e Satelec e Bordeux). In both cases, the Schneiderian membrane, covering the bony sinus, was gently separated from the sinus floor and elevated to contain graft material that is placed inferiorly. Careful sinus membrane elevation was performed and the presence or absence of perforation was evaluated. Ideal implant position was marked with a round burr. Using a surgical stent, the initial and serial drillings of the implant placement area were performed using implant’s burr sequence on an implant’s motors (Implacenter, Satelec, Bordeaux). The final drilling was performed with a counter sink when the bone density was really high. Implants used in this study are 187 Tixos (Leader, Novaxa-Italy); 51 cylindrical type (Leader, Novaxa e Italy) and 72 conic type (Leader, Novaxa-Italy). As regenerative materials authors used a resorbable membrane that was adapted on the regenerative tissues to protect it from the epithelial ingrowth and to allow the blood to refill the surgical site and make new bone. The membrane used in this study is pure collagen that is produced from bovine pericardium (Lyoplant Braun). A periosteal incision was given to make the flap more elastic and it permitted hermatic closure of the surgical site, by a suture with a 4/0 supramid (Supramid, Braun) for the crest incision and a 6/0 (Supramid, Braun) for lateral oblique releasing incisions.
Sutures were removed after 10 days. In all cases, no postsurgical infection or complications were detected (Fig. 2).
Radiographic data The radiographs (bitewings, periapical, and orthopantomogram for each patient) were taken at the end of the surgery appointment and immediately after the initial functional crown was placed (regardless of whether it was temporary or final) to serve for implant placement control and the baseline radiographic measurements for the sinus grafts and the crestal bone levels at time “zero” of initial loading. All radiographs were taken to ensure they were “diagnostic”. Bitewing radiographs (in which the entire length of the implant was most commonly visible) or OPG were taken again at a minimum of 12e48 months after functional loading of the implant and compared with those at baseline (ie, time of functional crown insertion). This radiographic evaluation, combined with the appropriate clinical criteria as described by Smith and Zarb39 in 1989, have been readily accepted as the reference standard (Fig. 3).
Implant success criteria Authors recorded the following criteria, suggested in international literature: No pain or tenderness on function; No mobility; Overall interproximal radiographic bone loss 2 mm from time of initial implant placement; Interproximal radiographic bone loss than 1.5 mm from the time of crown placement and initial functional loading to 1 year of functional loading; No pathologic peri-implant attachment loss indications (Table 2). Misch et al9 in 2008 explained these criteria which suggested that successful implants were those that did not experience any pain with function, any mobility, any exudate history, or more than 2 mm of radiographic bone loss since the placement date.19
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Fig. 2 Lateral access to the sinus lift in 3 different patients.
RESULTS This retrospective study was conducted on patients who underwent sinus bone grafts using a lateral approach and simultaneous implant placements performed by a single oral surgery from January 2006 to December 2007. The present analysis included 120 patients (52 woman and 68 male) between 24 and 70 years who needed prosthetic rehabilitation in posterior area. All patients wanted a fixed implant-supported prostheses. A total of 253 implant were placed at time 0 and only 45 were loaded after 8 months. At 6 weeks follow up 6 implants were lost, 3 in a woman 42 years old and 2 in a woman 49 years old. 1 implant was lost in a man 65 years old, 4 weeks after the surgery. In patients with an implant failure, another implant was placed 9 months after the implant removal. On 310 implants placed, 4 implants were lost between the 4th and the 6th weeks. The 292 implants were loaded with a total of 115 prostheses, between temporary or final restorations, and at each recall for the dental hygiene. Authors made a clinical or clinical and radiographical check of the implants. Three implants failed in 2 patients with prosthetic restoration loss.
At the time of the last follow up, the sinus bone graft resorption, crestal bone loss, and soft tissue condition (width of attached gingiva, plaque index, gingival inflammatory index, and probing depth) around the implants between the 3 types were not different. Implant success, in this retrospective study is 97.7% at 1 year follow up and 96.9% at 2 years follow up. Prosthetic success at a 4 year follow up (115 prosthetic treatment in 108 patients) has been 98% (Table 3).
DISCUSSION Generalized atrophy of the alveolar crest is compounded by pneumatization of the maxillary sinus, often rendering only a few millimeters of bone available for implant insertion. Different augmentation procedures have been developed. Sinus floor elevation plays an increasingly important role in oral surgery. Early reports by Tatum1 and Boyne6 described the lateral window technique. Implant therapy is being included in treatment plans more routinely because of its high success rates. Lack of available bone and enlarged sinus cavities are often a major obstacle to the placement of dental implants in the posterior maxilla. To increase the amount of bone in the maxilla, the sinus floor elevation procedure, or subantral augmentation,
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Fig. 3 3 One step sinus lift and implants placements in 3 different cases.
has been developed. This procedure involves placing bone graft material in the maxillary sinus to increase the height and width of the alveolus.3,6e16 Sinus augmentation with simultaneous implant placement has gained popularity and is now commonly used by more clinicians in the appropriate clinical circumstances therefore the decision to place an implant concurrently with sinus elevation surgery is usually determined by the Table 2 Implant’s height and width. Length 3.75 3.75 3.75 4.5 4.5 5 5
Width
Tixos
Conic
Cylindrical
Total
8 10 13 8 10 8 10
5 32 14 0 10 0 0 187
3 4 44 0 0 0 0 51
4 6 50 0 0 0 2 60
12 42 234 0 10 0 0 298
operator’s experience and the amount of residual sinus floor bone height the surgeon is comfortable with.4,5,37,38 Del Fabbro et al29 performed a systematic review of 39 selected studies (out of 252 screened as full text) in which 2046 patients underwent sinus-grafting and received 6913 implants. After a follow up period ranging from 12 to 75 months, an overall survival rate of 92.5% was reported (range, 61.2%e100%). Results were also divided according to the type of grafting materials. Overall, the survival rate of implants was 87.7% with autogenous bone, 94.9% when autogenous bone was mixed with other grafting materials, and 95.9% with non autogenous grafting materials. Results were also reported according to the type of implant surface. Overall, the survival rate was 85.6% for implants with smooth/machined surfaces, and 95.9% for implants with rough surfaces. This issue is still debated in the literature as there are still several schools of thought on this subject. A review of the literature by Chiapasco et al30 selected 57 studies (out of 470 screened as full text) in which 3163 patients were treated with 3947 sinus-grafting
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Table 3 Follow up. Implants Implants Implants Implants Total
presents success rate survival failed
Time 0
2 Months follow up
2 Years follow up
3 Years follow up
4 Years follow up
Rate%
298
292 97.9%
306 96.9%
306 96.9
306 96.9
98.7%
6 292
3 289
0 289
0 289
298
procedures and 8781 implants (3760 immediate, 3503 delayed, and 1518 nonspecified). In a longitudinal follow up study by Chiapasco et al.,31 692 patients underwent 952 sinus-grafting procedures (of whom 579 also received concomitant vertical and/or horizontal reconstruction with only grafts) and the placement of 2037 implants. After a mean follow up of 59 months (range, 12e 144 months), an overall survival rate of 95.8% was reported. On the other hand, different studies reported that the prognosis for performing maxillary sinus bone grafts first and placing implants second is good, and the delayed technique can reduce the risk of the infection of grafted bones. In addition, it has been reported that, compared with simultaneous implantation, delayed implantation allowed placement of implants in appropriate positions.33e35 Examining earlier research results on the selection of simultaneous versus delayed placement, it was found that the residual bone amount and the primary implant stability were important factors. Kim et al21 concluded that if cases are chosen appropriately to achieve primary stability, even in the cases in which bone grafts and implant placements are performed simultaneously and loading is placed at the time point of 4 months after placement, good results can be obtained. Chiapasco et al32 explained that the edentulous posterior maxilla may present an extremely wide variety of clinical situations, ranging from mild atrophy and sinus pneumatization to extreme 3-dimensional atrophy. Authors are convinced that every clinica case represents a “unique” situation not only as far as type of atrophy is concerned, but also in terms of other important factors, including post-operative morbidity, a patient’s expectations and compliance, number of surgical procedures needed, rehabilitation times, costs, and esthetic and functional outcome.
CONCLUSIONS On 298 implants the failure rate at 1 year follow up was 97.9%. At 2 years follow up the survival and success rate was 96.9% and a 4 years follow up it is still 96.9%. With all the limits of this retrospective study, made in a private practice with a limited number of patients, in accordance with Kim et al21 authors conclude that a complete pre
surgical planning and a careful patients selections can produce predictable results for implant prosthesis treatment. Prosthetic success at 4 year (115 prosthetic treatment in 108 patients) has been 98%.
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