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Localised maxillary ridge expansion with simultaneous implant placement: A case series
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British Journal of Oral and Maxillofacial Surgery 47 (2009) 535–540
Localised maxillary ridge expansion with simultaneous implant placement: A case series Federica Demarosi a,∗ , Giulio Cesare Leghissa b , Andrea Sardella a , Giovanni Lodi a , Antonio Carrassi a a b
Unit of Oral Pathology and Medicine, School of Dentistry, University of Milan, Via Beldiletto 1, 20142 Milano, Italy Studio Associato Leghissa Briata Via Raffaello Sanzio 31, 20149 Milano, Italy
Accepted 25 November 2008 Available online 15 January 2009
Abstract The placement of implants in edentulous areas is often compromised by a thin alveolar crest, which widens the space between the two cortical bones; this offers advantages from aesthetic, biomechanical, and functional points of view. We present our results using the osteotome technique for the creation of a site for an implant, followed by immediate placement of the implant in thin edentulous maxillae, and the stability of the bony expansion over time. Twenty-three patients (six men and seventeen women) with partial edentulism associated with horizontal resorption of the ridges were treated by this technique to obtain a wider bony base for better placement of the implants. At the same time, 36 endosseous titanium implants were inserted. Three to four months later, the patients were rehabilitated with implant-supported prostheses. All implants were successfully osseointegrated and loading began after 61–197 days. All implants inserted were 4.1 mm in diameter, and between 10 and 15 mm long. All the implant-supported prostheses functioned acceptably, with no signs or symptoms such as paraesthesiae, dysaesthesiae, or pain. Within the limits of this study this technique seems to be reliable and simple with little morbidity, and rehabilitation was as good as that after other techniques such as autogenous bone grafts or guided bone regeneration. Survival and the success of implants placed were consistent with those placed in non-reconstructed bone. © 2009 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved. Keywords: Osteotomes; Alveolar ridge augmentation; Oral implants
Introduction Dental rehabilitation of partially or totally edentulous patients with implants has become common practice in recent decades, with reliable long-term results.1 However, unfavourable local conditions in the alveolar ridge may make the use of dental implants difficult or impossible because of insufficient bone, or unfavourable vertical, transverse, or sagittal interarch relations. Reduction in the width of the edentulous ridge may make the final prosthetic results less than ideal from functional or aesthetic viewpoints because of the palatal or lingual position of the implants.2 ∗
Corresponding author. Tel.: +39 02 50319017; fax: +39 02 50319041. E-mail address: [email protected] (F. Demarosi).
To correct this, various techniques have been described for widening, including osteoinduction using appropriate growth factors, such as bone morphogenetic proteins (BMP),3 osteoconduction (where a graf serves as a scaffold for new bone),4 revascularised bone grafts,5 alveolar distraction osteogenesis,6 guided bone regeneration,7 and splitting to expand the ridge.2,8 However, these methods have limitations, including the need to harvest bone from intraoral or extr-oral sites, which may lead to increased morbidity, the risk of exposure of the bone graft or membrane followed by infection, and an unpredictable rate of bone resorption after the reconstructive or regenerative procedure(s) and placement of implants. We describe a single-step technique by which the bed of the implant is prepared by doing progressive osteotomies
0266-4356/$ – see front matter © 2009 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
doi:10.1016/j.bjoms.2008.11.012
536
F. Demarosi et al. / British Journal of Oral and Maxillofacial Surgery 47 (2009) 535–540
until the desired expansion is achieved, without ostectomy. Although success with this technique has been reported in clinical studies and case reports,9–13 data about long-term results are few. We present our results to evaluate the survival and success rates of implants placed in the treated areas, and to evaluate the stability of the bony expansion over time.
Patients and methods Patients were considered for the study if: they were having implants electively to restore partial edentulism; the width of the alveolar ridge was inferior to the optimally planned diameter of the implant (4.1 mm: the criterion used for implant placement is at least 1 mm of bone around the implant when in place)14 ; the width of the ridge was at least 1.5 mm; the alveolar ridge had undercuts that would lead to fenestration of the implant; the prosthetically driven placement of the implant required it to be in a given position on the arch where adequate bony dimensions were lacking; and aesthetic considerations in the maxilla required an increase of the vestibular–palatal dimensions. Exclusion criteria were: atrophic ridges (1.5 mm or less) with no interposition of cancellous bone between the buccal and palatal and lingual plates; a coexisting vertical defect; the use of tobacco; a history of radiotherapy to the head and neck region or treatment with bisphosphonates; active periodontal disease involving residual dentition; mucosal diseases such as lichen planus in the areas to be treated; poor oral hygiene; and lack of compliance. The surgical technique and study protocol were explained to the patients, and written informed consent was obtained. Panoramic radiographs were obtained before, and immediately and 6 months after, the placement of implants. Computed tomograms (CT) were obtained preoperatively to evaluate horizontal defects and whether there was cancellous bone between the buccal and palatal and lingual plates. We used cylindroconical expansion osteotomes (Straumann® , Germany) that gradually escalated in diameter from one instrument to the next, so that the base of each instrument corresponded to the active portion of the next instrument. The apical portion of the instrument was cylindroconical, and there were four diameters (2.2, 2.8, 3.5, and 4.2 mm) marked at different lengths. We also used a pilot drill that measured 1.7 mm in diameter (Bone System, Milan, Italy) and Bone System Implants (Bone System, Milan, Italy).
Fig. 1. A pilot drill with no internal irrigation (Bone System, Milan, Italy), measuring 1.7 mm in diameter, created the insertion axis.
Fig. 2. The smallest calibre expansion osteotome (2.2 mm) inserted into the bony crest.
charges of soft tissue were used to facilitate visual access to the bony crest. At the planned implant sites, a pilot drill with no internal irrigation (Bone System, Milan, Italy), that measured 1.7 mm in diameter, was used to create the insertion axis (Fig. 1). We then used percussion with the smallest calibre expansion osteotome (2.2 mm) until the layer was perforated, followed by insertion of the next smallest osteotome (2.8 mm), working through successively larger instruments (3.5 and 4.2 mm) (Figs. 2 and 3). The expansion osteotomes were inserted man-
Operative technique The technique consisted of preparing the implant bed by progressively increasing the size of the osteotomes until the desired expansion was achieved. Under local infiltration anaesthesia, full-thickness flaps were raised through a midcrestal incision. When appropriate, mesial and distal dis-
Fig. 3. The larger osteotome (4.2 mm) inserted into the bony crest.
F. Demarosi et al. / British Journal of Oral and Maxillofacial Surgery 47 (2009) 535–540
537
Associates Inc., USA). Sutures were removed 7–10 days postoperatively. All patients were given amoxicillin 1 g orally twice a day starting the day before operation and continuing for 5 days. Postoperative care consisted of rinsing with 0.2% chlorhexidine twice daily for 10 days, and a soft diet. Non-steroidal analgesics were prescribed as needed for pain control. Three to four months after placement of the implants, abutments were connected and prosthetic rehabilitation begun. Follow-up and criteria for success Fig. 4. The Bone System® implant in place.
ually, and pressed and rotated at the same time until the desired height was reached, or until we encountered resistance. Once the desired depth had been reached, and before we moved on to the next instrument, we waited 1–2 min for bony microfractures to form and dilate and compact the adjacent bone.15 After the bed had been prepared, we inserted the implant immediately to prevent the socket from collapsing (Fig. 4). Implants were inserted flush with the bone until final seating, following the Bone System® method (Bone System, Milan, Italy). The fixation must be placed with caution to avoid fractures or dehiscences of the vestibular table, which is sometimes thin. Provided that they do not compromise primary stability of the implant, these vertical fractures of the vestibular cortical layer are of little importance as they consolidate during osseointegration. After the implant had been placed, the wound was closed primarily with interrupted, synthetic, non-absorbable sutures (Supramid, Assut sutures® , Assut Medical Sarl, Switzerland) and the implant was left to heal (Fig. 5). In cases of fracture of the buccal cortical bone with movement of the implant, we used Bio-Oss® spongiosa granules (0.25–1.0 mm, Geistlich, Wolhusen, Switzerland), autogenous bone chips, and a bioabsorbable membrane (Gore Resolut XT® regenerative membrane, W.L. Gore &
Fig. 5. Primary would closure with interrupted synthetic, non-absorbable sutures.
Patients were followed up 3, 6, and 12 months postoperatively and then annually with visual and radiographic examinations. Criteria for success included: effective placement and primary stability of the planned implant; stability of the implant at each visit (lack of mobility); absence of pain or any subjective sensation at each visit; lack of peri-implant infection with suppuration; and lack of continuous radiolucency around the implant.14
Results Between November 2002 and December 2007, 23 consecutive, healthy, non-smoking, adult patients with atrophy of the upper maxilla had 26 procedures and 36 implants inserted. There were 17 women and 6 men, mean age 56 years (range 18–74). Clinical and personal details of patients, and the number, type, and sites of implants are shown in Table 1. All implants were positioned anteriorly by the same surgeon (Table 2). The width of the alveolar ridge was measured with calipers. The measurements were made with open flaps at the time of operation, and through the mucosa at the time of loading, to avoid reopening the sites. The initial width of the alveolar ridge ranged from 2.5 to 4.5 mm (median 3.6), while at the end of the expansion procedure it ranged from 6 to 7.5 mm (median 6.8) (Fig. 6a and b). The gain in alveolar bone ranged from 3 to 5 mm. All implants were 4.1 mm in diameter, and 10 (n = 1), 12 (n = 16), or 15 (n = 18) mm long. All implants were placed on the same day as the bone was expanded. During preparation of the implant site we used autogenous bone chips that were harvested when the bone was drilled, plus bone from bovine sources (Bio-Oss® spongiosa granules) in 6 of the 26 procedures (Table 1). This combination of graft material and autogenous particles was used to cover the exposed surface of the implants; in these cases, a bioabsorbable membrane (Gore Resolut XT® regenerative membrane, W.L. Gore & Associates Inc., USA) was also put in place to promote bony regeneration. No infection was noted during the postoperative period and healing was uneventful. All implants successfully osseointegrated and no implant was removed when the abutment was connected or before or
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F. Demarosi et al. / British Journal of Oral and Maxillofacial Surgery 47 (2009) 535–540
Table 1 Characteristics of patients. Case number
Age (years)
Sex (M/F)
Implant site
Number of implants
Type of implants (diameter × length) (mm)
Timing of loading (days)
Follow-up after loading (months)
Graft
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
55 56 59 74 18 74 70 58 64 50 69 56 51 39 55 47
F F F F F M F M F F F F F M F F
1 1 1 2 1 2 1 1 1 2 2 1 1 1 2 6
4.1 × 12 4.1 × 15 4.1 × 15 4.1 × 12, 4.1 × 10 4.1 × 15 4.1 × 15, 4.1 × 15 4.1 × 12 4.1 × 15 4.1 × 15 4.1 × 12 4.1 × 12, 4.1 × 12 4.1 × 15 4.1 × 15 4.1 × 12 4.1 × 15, 4.1 × 12 4.1 × 12 (all)
115 81 110 61 103 197 78 94 97 100 154 104 141 161 104 170
36 No 9 12 52 12 13 47 11 40 3 17 63 21 62 16
Yes No No No Yes No No Yes Yes No No Yes No Yes No No
17 18 19 20 21 22 23
56 33 51 73 55 55 59
F M M M F F F
21 15 23 22, 23 12 21, 23 14 14 11 21, 11 14, 24 12 24 14 24, 25 13, 14, 15, 23, 24, 25 12 22 15, 14, 24 25 21 14 22
1 1 3 1 1 1 1
4.1 × 12 4.1 × 15 4.1 × 15 (all) 4.1 × 15 4.1 × 15 4.1 × 12 4.1 × 15
156 121 105 75 98 127 96
15 14 15 9 45 9 64
No No No No No No Yes
Fig. 6. Occlusal view of the ridge in case 3 before and after expansion.
during follow-up. Loading began after 61–197 days (mean 115), and follow-up ranged from 6 to 68 months (mean 30), calculated from the day of expansion. One patient (who had one implant) dropped out of the follow-up phase 3 months after the expansion procedure (immediately after loading) because he had gone abroad. The period of observation after loading of the implants ranged from 3 to 64 months (mean 26). All 35 completed implants fulfilled our criteria of success based on clinical and radiographic examination, and were classified as successful implants (implant success rate = 97%). All patients had acceptable function of the implant-supported prostheses, with no pathological signs or symptoms and a satisfactory cosmetic result (Fig. 7a–c).
Table 2 Distribution of implants by site. Tooth no.
No. of implants (n = 35)
16 15 14 13 12 11 21 22 23 24 25 26
0 3a 7 1 3 2 4 3 4 5 3 0 a
Patient who dropped out (one implant).
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Fig. 7. Occlusal view of the ridge before expansion (a), the cosmetic result after 6 months (b), and the cosmetic result after 2 years (c), in case 18.
Discussion A common anatomical limitation in oral implantology is atrophy of the upper maxilla. There are several possible causes of this, including periodontal disease, trauma, and developmental anomalies. Resorption of bone after loss of a tooth has a certain pattern in which the labial aspect of the alveolus is resorbed, which first reduces its width and later its height. The placement of endosseous implants in an atrophic jaw is often limited by the limited amount of alveolar bone available.16 To avoid this, different procedures such as bone grafting, guided bone regeneration, and bone splitting are currently used to correct narrow ridges, together with the placement of dental implants.2,8 We have described a single-step technique for bony expansion using cylindroconical osteotomes with gradually escalating diameters, and immediately placement of the implants. This technique, originally reported by Summers,17 takes advantage of the fact that bone is viscoelastic and can be compressed and manipulated. Osteotomes do not excise bone during preparation of the bed; rather, they exert lateral compression, which increases bone density and encourages primary retention of the implant.15 The technique is particularly useful in the upper maxilla, because the lower bone density and thinner cortical buccal plate allows perforation,
lateral compression, and expansion of the adjacent bone. When the osteotome technique is used, the thin alveolar crest becomes similar to an alveolus after extraction, where the presence of the coagulum is sufficient to ensure proper healing of the tissues, wand there is no need for barrier devices around the implants. The target is to increase the density and volume of the spongiose bone by compression in the apicocoronal and buccolingual dimensions.18 This healing may also be promoted by the surfaces of the implant. Some studies have shown that the surface of the implant can influence the production of cytokines, growth factors, and phenotypic expression of cells, and consequently modulate the healing process in the tissues.19 Our results have shown that bony expansion using osteotomes is a reliable and relatively non-invasive way of widening narrow ridges. We achieved 97% survival and success rates of implants placed in the expanded ridges; this is consistent with those related to implants placed in native, unreconstructed bone. We think that expansion of the ridge with osteotomes has several advantages over other augmentation techniques. First, heat has a detrimental effect on osseointegration, and the osteotome technique produces less peri-implant warming of the bone and eliminates its loss during expansion. Secondly, compared with standard sagittal osteotomy in which the atro-
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phied site is expanded with chisels, the use of osteotomes may allow a more gradual widening of the ridge, with less risk of fracturing the cut segments. Unlike guided bone regeneration or onlay grafting, the expansion of atrophic ridges by the osteotome technique does not require harvesting of bone, reduces operating time and postoperative morbidity, shortens rehabilitation time, and eliminates the risk of exposure of the membrane or bone graft that could lead to infection. Good gingival aesthetic results in the anterior sector require sufficient width of bone, and osteotomes are a useful option. We have treated 26 anterior sites, and in most cases obtained a correct profile of the soft tissue to correspond to the implants. The limitations of this procedure include the possibility of treating only horizontal defects, and the necessity for spongy bone within the buccal and palatal and lingual plates. To have to tap of the expansion osteotomes with the surgical mallet is a rare inconvenience of the technique, and occasionally it may induce benign paroxysmal positional vertigo in patients who have not experienced previous episodes.20 Within the limits of this study we can the following conclusions: the technique was relatively simple and the incidence of operative and postoperative complications was limited; success and survival of implants placed in the expanded areas were within the limits of criteria proposed by Albrektsson et al.14 and were consistent with those of implants placed in native bone; peri-implant clinical measurements were consistent with those reported elsewhere21,22 ; and the expansion of narrow ridges with osteotomes was stable over time with limited resorption of buccal bone, as shown at postoperative follow-up.
References 1. Chiapasco M, Ferrini F, Casentini P, Accardi S, Zaniboni M. Dental implants placed in expanded narrow edentulous ridges with the Extension Crests device. A 1–3-year multicenter follow-up study. Clin Oral Implants Res 2006;17:265–72. 2. Chiapasco M, Zaniboni M, Boisco M. Augmentation procedures for the rehabilitation of deficient edentulous ridges with oral implants. Clin Oral Implants Res 2006;17(Suppl. 2):136–59. 3. Reddi AH, Wientroub S, Muthukumaran N. Biologic principles of bone induction. Orthop Clin North Am 1987;18:207–12. 4. Burchardt H. The biology of bone graft repair. Clin Orthop Relat Res 1983;(174):28–42.
5. Hidalgo DA. Fibula free flap: a new method of mandible reconstruction. Plast Reconstr Surg 1989;84:71–9. 6. Ilizarov GA. The tension-stress effect on the genesis and growth of tissues: Part II. The influence of the rate and frequency of distraction. Clin Orthop Relat Res 1989;(239):263–85. 7. Hämmerle CH, Jung RE, Feloutzis A. A systematic review of the survival of implants in bone sites augmented with barrier membranes (guided bone regeneration) in partially edentulous patients. J Clin Periodontol 2002;29(Suppl. 3):226–33. 8. Simion M, Baldoni M, Zaffe D. Jawbone enlargement using immediate implant placement associated with a split-crest technique and guided tissue regeneration. Int J Periodontics Restorative Dent 1992;12:462–73. 9. Horowitz RA. The use of osteotomes for sinus augmentation at the time of implant placement. Compend Contin Educ Dent 1997;18:441–7. 10. Komarnyckyj OG, London RM. Osteotome single-stage dental implant placement with and without sinus elevation: a clinical report. Int J Oral Maxillofac Implants 1998;13:799–804. 11. Davarpanah M, Martinez H, Tecucianu JF, Hage G, Lazzara R. The modified osteotome technique. Int J Periodontics Restorative Dent 2001;21:599–607. 12. Glauser G, Naef R, Scharer P. The osteotome technique. A different method of implant placement in the posterior maxilla. Implantologie 1998;2:103–20. 13. Hahn J. Clinical use of osteotomes. J Oral Implant 1999;25:23–9. 14. Albrektsson T, Zarb G, Worthington P, Eriksson AR. The long-term efficacy of currently used dental implants: a review and proposed criteria of success. Int J Oral Maxillofac Implants 1986;1:11–25. 15. Buchter A, Kleinheinz J, Wiesmann HP, Kersken J, Nienkemper M, Weyhrother H, et al. Biological and biomechanical evaluation of bone remodelling and implant stability after using an osteotome technique. Clin Oral Implants Res 2005;16:1–8. 16. Guirado JL, Yuguero MR, Carrion del Valle MJ, Zamora GP. A maxillary ridge-splitting technique followed by immediate placement of implants: a case report. Implant Dent 2005;14:14–20. 17. Summers RB. A new concept in maxillary implant surgery: the osteotome technique. Compendium 1994;15:152–8. 18. Rambla-Ferrer J, Penarrocha-Diago M, Guarinos-Carbo J. Analysis of the use of expansion osteotomes for the creation of implant beds. Technical contributions and review of the literature. Med Oral Patol Oral Cir Bucal 2006;11:267–71. 19. Rimondini L, Bruschi GB, Scipioni A, Carrassi A, Nicoli-Aldini N, Giavaresi G, et al. Tissue healing in implants immediately placed into postextraction sockets: a pilot study in a mini-pig model. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2005;100:43–50. 20. Pe˜narrocha M, Pérez H, Garciá A, Guarinos J. Benign paroxysmal positional vertigo as a complication of osteotome expansion of the maxillary alveolar ridge. J Oral Maxillofac Surg 2001;59:106–7. 21. Nishimura K, Itoh T, Takaki K, Hosakawa R, Naito T, Yokota M. Periodontal parameters of osseointegrated dental implants. A 4-year controlled follow-up study. Clin Oral Implants Res 1997;8:272–8. 22. Leonhardt A, Gröndahl K, Bergström C, Lekholm U. Long-term followup of osseointegrated titanium implants using clinical, radiographic and microbiological parameters. Clin Oral Implants Res 2002;13:127–32.
British Journal of Oral and Maxillofacial Surgery 47 (2009) 535–540
Localised maxillary ridge expansion with simultaneous implant placement: A case series Federica Demarosi a,∗ , Giulio Cesare Leghissa b , Andrea Sardella a , Giovanni Lodi a , Antonio Carrassi a a b
Unit of Oral Pathology and Medicine, School of Dentistry, University of Milan, Via Beldiletto 1, 20142 Milano, Italy Studio Associato Leghissa Briata Via Raffaello Sanzio 31, 20149 Milano, Italy
Accepted 25 November 2008 Available online 15 January 2009
Abstract The placement of implants in edentulous areas is often compromised by a thin alveolar crest, which widens the space between the two cortical bones; this offers advantages from aesthetic, biomechanical, and functional points of view. We present our results using the osteotome technique for the creation of a site for an implant, followed by immediate placement of the implant in thin edentulous maxillae, and the stability of the bony expansion over time. Twenty-three patients (six men and seventeen women) with partial edentulism associated with horizontal resorption of the ridges were treated by this technique to obtain a wider bony base for better placement of the implants. At the same time, 36 endosseous titanium implants were inserted. Three to four months later, the patients were rehabilitated with implant-supported prostheses. All implants were successfully osseointegrated and loading began after 61–197 days. All implants inserted were 4.1 mm in diameter, and between 10 and 15 mm long. All the implant-supported prostheses functioned acceptably, with no signs or symptoms such as paraesthesiae, dysaesthesiae, or pain. Within the limits of this study this technique seems to be reliable and simple with little morbidity, and rehabilitation was as good as that after other techniques such as autogenous bone grafts or guided bone regeneration. Survival and the success of implants placed were consistent with those placed in non-reconstructed bone. © 2009 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved. Keywords: Osteotomes; Alveolar ridge augmentation; Oral implants
Introduction Dental rehabilitation of partially or totally edentulous patients with implants has become common practice in recent decades, with reliable long-term results.1 However, unfavourable local conditions in the alveolar ridge may make the use of dental implants difficult or impossible because of insufficient bone, or unfavourable vertical, transverse, or sagittal interarch relations. Reduction in the width of the edentulous ridge may make the final prosthetic results less than ideal from functional or aesthetic viewpoints because of the palatal or lingual position of the implants.2 ∗
Corresponding author. Tel.: +39 02 50319017; fax: +39 02 50319041. E-mail address: [email protected] (F. Demarosi).
To correct this, various techniques have been described for widening, including osteoinduction using appropriate growth factors, such as bone morphogenetic proteins (BMP),3 osteoconduction (where a graf serves as a scaffold for new bone),4 revascularised bone grafts,5 alveolar distraction osteogenesis,6 guided bone regeneration,7 and splitting to expand the ridge.2,8 However, these methods have limitations, including the need to harvest bone from intraoral or extr-oral sites, which may lead to increased morbidity, the risk of exposure of the bone graft or membrane followed by infection, and an unpredictable rate of bone resorption after the reconstructive or regenerative procedure(s) and placement of implants. We describe a single-step technique by which the bed of the implant is prepared by doing progressive osteotomies
0266-4356/$ – see front matter © 2009 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
doi:10.1016/j.bjoms.2008.11.012
536
F. Demarosi et al. / British Journal of Oral and Maxillofacial Surgery 47 (2009) 535–540
until the desired expansion is achieved, without ostectomy. Although success with this technique has been reported in clinical studies and case reports,9–13 data about long-term results are few. We present our results to evaluate the survival and success rates of implants placed in the treated areas, and to evaluate the stability of the bony expansion over time.
Patients and methods Patients were considered for the study if: they were having implants electively to restore partial edentulism; the width of the alveolar ridge was inferior to the optimally planned diameter of the implant (4.1 mm: the criterion used for implant placement is at least 1 mm of bone around the implant when in place)14 ; the width of the ridge was at least 1.5 mm; the alveolar ridge had undercuts that would lead to fenestration of the implant; the prosthetically driven placement of the implant required it to be in a given position on the arch where adequate bony dimensions were lacking; and aesthetic considerations in the maxilla required an increase of the vestibular–palatal dimensions. Exclusion criteria were: atrophic ridges (1.5 mm or less) with no interposition of cancellous bone between the buccal and palatal and lingual plates; a coexisting vertical defect; the use of tobacco; a history of radiotherapy to the head and neck region or treatment with bisphosphonates; active periodontal disease involving residual dentition; mucosal diseases such as lichen planus in the areas to be treated; poor oral hygiene; and lack of compliance. The surgical technique and study protocol were explained to the patients, and written informed consent was obtained. Panoramic radiographs were obtained before, and immediately and 6 months after, the placement of implants. Computed tomograms (CT) were obtained preoperatively to evaluate horizontal defects and whether there was cancellous bone between the buccal and palatal and lingual plates. We used cylindroconical expansion osteotomes (Straumann® , Germany) that gradually escalated in diameter from one instrument to the next, so that the base of each instrument corresponded to the active portion of the next instrument. The apical portion of the instrument was cylindroconical, and there were four diameters (2.2, 2.8, 3.5, and 4.2 mm) marked at different lengths. We also used a pilot drill that measured 1.7 mm in diameter (Bone System, Milan, Italy) and Bone System Implants (Bone System, Milan, Italy).
Fig. 1. A pilot drill with no internal irrigation (Bone System, Milan, Italy), measuring 1.7 mm in diameter, created the insertion axis.
Fig. 2. The smallest calibre expansion osteotome (2.2 mm) inserted into the bony crest.
charges of soft tissue were used to facilitate visual access to the bony crest. At the planned implant sites, a pilot drill with no internal irrigation (Bone System, Milan, Italy), that measured 1.7 mm in diameter, was used to create the insertion axis (Fig. 1). We then used percussion with the smallest calibre expansion osteotome (2.2 mm) until the layer was perforated, followed by insertion of the next smallest osteotome (2.8 mm), working through successively larger instruments (3.5 and 4.2 mm) (Figs. 2 and 3). The expansion osteotomes were inserted man-
Operative technique The technique consisted of preparing the implant bed by progressively increasing the size of the osteotomes until the desired expansion was achieved. Under local infiltration anaesthesia, full-thickness flaps were raised through a midcrestal incision. When appropriate, mesial and distal dis-
Fig. 3. The larger osteotome (4.2 mm) inserted into the bony crest.
F. Demarosi et al. / British Journal of Oral and Maxillofacial Surgery 47 (2009) 535–540
537
Associates Inc., USA). Sutures were removed 7–10 days postoperatively. All patients were given amoxicillin 1 g orally twice a day starting the day before operation and continuing for 5 days. Postoperative care consisted of rinsing with 0.2% chlorhexidine twice daily for 10 days, and a soft diet. Non-steroidal analgesics were prescribed as needed for pain control. Three to four months after placement of the implants, abutments were connected and prosthetic rehabilitation begun. Follow-up and criteria for success Fig. 4. The Bone System® implant in place.
ually, and pressed and rotated at the same time until the desired height was reached, or until we encountered resistance. Once the desired depth had been reached, and before we moved on to the next instrument, we waited 1–2 min for bony microfractures to form and dilate and compact the adjacent bone.15 After the bed had been prepared, we inserted the implant immediately to prevent the socket from collapsing (Fig. 4). Implants were inserted flush with the bone until final seating, following the Bone System® method (Bone System, Milan, Italy). The fixation must be placed with caution to avoid fractures or dehiscences of the vestibular table, which is sometimes thin. Provided that they do not compromise primary stability of the implant, these vertical fractures of the vestibular cortical layer are of little importance as they consolidate during osseointegration. After the implant had been placed, the wound was closed primarily with interrupted, synthetic, non-absorbable sutures (Supramid, Assut sutures® , Assut Medical Sarl, Switzerland) and the implant was left to heal (Fig. 5). In cases of fracture of the buccal cortical bone with movement of the implant, we used Bio-Oss® spongiosa granules (0.25–1.0 mm, Geistlich, Wolhusen, Switzerland), autogenous bone chips, and a bioabsorbable membrane (Gore Resolut XT® regenerative membrane, W.L. Gore &
Fig. 5. Primary would closure with interrupted synthetic, non-absorbable sutures.
Patients were followed up 3, 6, and 12 months postoperatively and then annually with visual and radiographic examinations. Criteria for success included: effective placement and primary stability of the planned implant; stability of the implant at each visit (lack of mobility); absence of pain or any subjective sensation at each visit; lack of peri-implant infection with suppuration; and lack of continuous radiolucency around the implant.14
Results Between November 2002 and December 2007, 23 consecutive, healthy, non-smoking, adult patients with atrophy of the upper maxilla had 26 procedures and 36 implants inserted. There were 17 women and 6 men, mean age 56 years (range 18–74). Clinical and personal details of patients, and the number, type, and sites of implants are shown in Table 1. All implants were positioned anteriorly by the same surgeon (Table 2). The width of the alveolar ridge was measured with calipers. The measurements were made with open flaps at the time of operation, and through the mucosa at the time of loading, to avoid reopening the sites. The initial width of the alveolar ridge ranged from 2.5 to 4.5 mm (median 3.6), while at the end of the expansion procedure it ranged from 6 to 7.5 mm (median 6.8) (Fig. 6a and b). The gain in alveolar bone ranged from 3 to 5 mm. All implants were 4.1 mm in diameter, and 10 (n = 1), 12 (n = 16), or 15 (n = 18) mm long. All implants were placed on the same day as the bone was expanded. During preparation of the implant site we used autogenous bone chips that were harvested when the bone was drilled, plus bone from bovine sources (Bio-Oss® spongiosa granules) in 6 of the 26 procedures (Table 1). This combination of graft material and autogenous particles was used to cover the exposed surface of the implants; in these cases, a bioabsorbable membrane (Gore Resolut XT® regenerative membrane, W.L. Gore & Associates Inc., USA) was also put in place to promote bony regeneration. No infection was noted during the postoperative period and healing was uneventful. All implants successfully osseointegrated and no implant was removed when the abutment was connected or before or
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Table 1 Characteristics of patients. Case number
Age (years)
Sex (M/F)
Implant site
Number of implants
Type of implants (diameter × length) (mm)
Timing of loading (days)
Follow-up after loading (months)
Graft
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
55 56 59 74 18 74 70 58 64 50 69 56 51 39 55 47
F F F F F M F M F F F F F M F F
1 1 1 2 1 2 1 1 1 2 2 1 1 1 2 6
4.1 × 12 4.1 × 15 4.1 × 15 4.1 × 12, 4.1 × 10 4.1 × 15 4.1 × 15, 4.1 × 15 4.1 × 12 4.1 × 15 4.1 × 15 4.1 × 12 4.1 × 12, 4.1 × 12 4.1 × 15 4.1 × 15 4.1 × 12 4.1 × 15, 4.1 × 12 4.1 × 12 (all)
115 81 110 61 103 197 78 94 97 100 154 104 141 161 104 170
36 No 9 12 52 12 13 47 11 40 3 17 63 21 62 16
Yes No No No Yes No No Yes Yes No No Yes No Yes No No
17 18 19 20 21 22 23
56 33 51 73 55 55 59
F M M M F F F
21 15 23 22, 23 12 21, 23 14 14 11 21, 11 14, 24 12 24 14 24, 25 13, 14, 15, 23, 24, 25 12 22 15, 14, 24 25 21 14 22
1 1 3 1 1 1 1
4.1 × 12 4.1 × 15 4.1 × 15 (all) 4.1 × 15 4.1 × 15 4.1 × 12 4.1 × 15
156 121 105 75 98 127 96
15 14 15 9 45 9 64
No No No No No No Yes
Fig. 6. Occlusal view of the ridge in case 3 before and after expansion.
during follow-up. Loading began after 61–197 days (mean 115), and follow-up ranged from 6 to 68 months (mean 30), calculated from the day of expansion. One patient (who had one implant) dropped out of the follow-up phase 3 months after the expansion procedure (immediately after loading) because he had gone abroad. The period of observation after loading of the implants ranged from 3 to 64 months (mean 26). All 35 completed implants fulfilled our criteria of success based on clinical and radiographic examination, and were classified as successful implants (implant success rate = 97%). All patients had acceptable function of the implant-supported prostheses, with no pathological signs or symptoms and a satisfactory cosmetic result (Fig. 7a–c).
Table 2 Distribution of implants by site. Tooth no.
No. of implants (n = 35)
16 15 14 13 12 11 21 22 23 24 25 26
0 3a 7 1 3 2 4 3 4 5 3 0 a
Patient who dropped out (one implant).
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Fig. 7. Occlusal view of the ridge before expansion (a), the cosmetic result after 6 months (b), and the cosmetic result after 2 years (c), in case 18.
Discussion A common anatomical limitation in oral implantology is atrophy of the upper maxilla. There are several possible causes of this, including periodontal disease, trauma, and developmental anomalies. Resorption of bone after loss of a tooth has a certain pattern in which the labial aspect of the alveolus is resorbed, which first reduces its width and later its height. The placement of endosseous implants in an atrophic jaw is often limited by the limited amount of alveolar bone available.16 To avoid this, different procedures such as bone grafting, guided bone regeneration, and bone splitting are currently used to correct narrow ridges, together with the placement of dental implants.2,8 We have described a single-step technique for bony expansion using cylindroconical osteotomes with gradually escalating diameters, and immediately placement of the implants. This technique, originally reported by Summers,17 takes advantage of the fact that bone is viscoelastic and can be compressed and manipulated. Osteotomes do not excise bone during preparation of the bed; rather, they exert lateral compression, which increases bone density and encourages primary retention of the implant.15 The technique is particularly useful in the upper maxilla, because the lower bone density and thinner cortical buccal plate allows perforation,
lateral compression, and expansion of the adjacent bone. When the osteotome technique is used, the thin alveolar crest becomes similar to an alveolus after extraction, where the presence of the coagulum is sufficient to ensure proper healing of the tissues, wand there is no need for barrier devices around the implants. The target is to increase the density and volume of the spongiose bone by compression in the apicocoronal and buccolingual dimensions.18 This healing may also be promoted by the surfaces of the implant. Some studies have shown that the surface of the implant can influence the production of cytokines, growth factors, and phenotypic expression of cells, and consequently modulate the healing process in the tissues.19 Our results have shown that bony expansion using osteotomes is a reliable and relatively non-invasive way of widening narrow ridges. We achieved 97% survival and success rates of implants placed in the expanded ridges; this is consistent with those related to implants placed in native, unreconstructed bone. We think that expansion of the ridge with osteotomes has several advantages over other augmentation techniques. First, heat has a detrimental effect on osseointegration, and the osteotome technique produces less peri-implant warming of the bone and eliminates its loss during expansion. Secondly, compared with standard sagittal osteotomy in which the atro-
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phied site is expanded with chisels, the use of osteotomes may allow a more gradual widening of the ridge, with less risk of fracturing the cut segments. Unlike guided bone regeneration or onlay grafting, the expansion of atrophic ridges by the osteotome technique does not require harvesting of bone, reduces operating time and postoperative morbidity, shortens rehabilitation time, and eliminates the risk of exposure of the membrane or bone graft that could lead to infection. Good gingival aesthetic results in the anterior sector require sufficient width of bone, and osteotomes are a useful option. We have treated 26 anterior sites, and in most cases obtained a correct profile of the soft tissue to correspond to the implants. The limitations of this procedure include the possibility of treating only horizontal defects, and the necessity for spongy bone within the buccal and palatal and lingual plates. To have to tap of the expansion osteotomes with the surgical mallet is a rare inconvenience of the technique, and occasionally it may induce benign paroxysmal positional vertigo in patients who have not experienced previous episodes.20 Within the limits of this study we can the following conclusions: the technique was relatively simple and the incidence of operative and postoperative complications was limited; success and survival of implants placed in the expanded areas were within the limits of criteria proposed by Albrektsson et al.14 and were consistent with those of implants placed in native bone; peri-implant clinical measurements were consistent with those reported elsewhere21,22 ; and the expansion of narrow ridges with osteotomes was stable over time with limited resorption of buccal bone, as shown at postoperative follow-up.
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