REVIEW
Prosthetically driven Implant Placement. How to achieve
the appropriate implant site development
Federico Brugnami and Cristiano Calefﬁ
Private Practice, Rome, Italy(Received for publication on March 23, 2005)(Revised for publication on June 27, 2005)(Accepted for publication on August 24, 2005)

Abstract. Dental implants are established alternatives for replacing missing teeth. Tooth loss for different reasons may leads to alveolar resorption. Shortage of bone can prevent proper positioning ofdental implants according to prosthetic needs and treatment planning, unless the volume of hard andsoft tissues is increased before implantation. In the esthetic area it is essential not only to achieve wellanchored implants but also sufﬁcient soft and hard tissue in order to obtain natural looking result. This
article will present several treatment modalities to augment the soft and hard tissues in order to obtainproper insertion of implants according to prosthetic needs and patient satisfaction. (Keio J Med 54 (4):172–178, December 2005)
Key words: dental implants, ridge augmentation, surgical techniques, prosthetic guidance

Introduction

Alveolar Bone Resorption After Tooth Loss

Implantology has undergone a number of phases.
The developing phase was the period during which we
determined whether implants could be placed successfully with achievement of osteointegration. The prosthetic phase represented the development of prosthetic
components and techniques that would afford the clinician the ability to place esthetic restorations. Today werealize that for a completely functional and esthetic
restoration a complete hard and soft tissue harmony has
to be achieved before or during implant placement.
Augmentation of the resorbed alveolar crest, for example, can be achieved with soft and hard tissue onlays,
bone grafts, membrane techniques, bone distraction andbone splitting, maxillary sinus ﬂoor elevation and bone
grafting. Bone grafting and guided bone regeneration
can increase the width and, to some extent, also theheight of the alveolar bone.1,2 Lateral widening, but
not vertical augmentation, is possible with a crestal
split technique.3,4 All of these treatments are very
technique-sensitive and have clear indication andcontra-indication.

Alveolar bone is a specialized part of mandibular
and maxillary bone that forms the primary support forteeth. It is composed of bundles of bone, which is built
up in layers in a parallel orientation to the coronalapical direction of the tooth. The anterior maxillarybone is less dense than mandibular bone but more
dense than maxillary posterior bone.5 Alveolar ridge
defects and deformities can be the results of trauma,
periodontal disease, surgical treatment or congenitalmaldevelopment. Resorption after tooth loss has beenshown to follow a certain pattern: the labial site ofalveolar crest is primarily resorbed, which ﬁrst reduces
its width and later the height.6,7 Alveolar bone isresorbed after tooth extraction or avulsion most rapidly
during the ﬁrst years. Extraction of anterior maxillaryteeth is associated with a progressive loss of bone
mainly from the labial side.7 The loss is estimated to be
40–60% during the ﬁrst 3 years and decreases to 0.25–
0.5% annual loss thereafter.8 The cause for resorptionof alveolar bone has been assumed to be due to disuse
atrophy, decreased blood supply, localized inﬂamma-

Reprint requests to: Dr. Federico Brugnami, Piazza Prati degli Strozzi, 21, 00195 Rome, Italy, e-mail: info@parodontologiaimpianti.it
172

Keio J Med 2005; 54 (4): 172–178

tion or prosthesis pressure.8 In order to preserve theform of alveolar crest after tooth loss, some root replicates have been introduced. These are made of e.g.
PLA9 or bioglass10 and are able to preserve the crestal
width and height but may impair later implantation due
to incomplete resorption. Also, autogenous grafts and/or allografts11,12 and non-resorbable13,14 or resorbablemembranes15 have been used to ﬁll the bone defects
and to prevent resorption after tooth loss. Soft tissue
augmentation has been achieved with sub-epithelial
connective tissue grafts, which preserve gingival color
and tissue characteristics.16,17 Allogenic grafts andvarious techniques have also been used for esthetic
reasons to maintain the bone and soft tissue level underneath the pontic area in ﬁxed bridges18 and in
improving appearance before prosthetic treatment inlocalized alveolar ridge defects.19

173

Fig. 1.1

Autogenous block in place form retro-molar area.

Augmentation with Bone Grafts
Autogenous bone is still considered the golden standard in the bone regeneration procedures (Figs. 1.1 to
1.3).20 Studies have shown that autogenous cancellous
bone produces successful and predictable results.20
Autogenous bone grafts may act mostly as scaffolds andare thus more osteoconductive than osteoinductive eventhough osteogenic activity may have remained in the
spongious part of the graft.21 The disadvantages of
autogenous grafts are the need for a second surgical site
and its associated morbidity.22 Autogenous grafts canbe taken, in fact, in lower volume from the maxillofacial area or in greater volume from distant sites suchas iliac crest, tibia, ﬁbula and even scapula. Intra-oralbone grafting is generally sufﬁcient in treating narrowmaxillary alveolar crest. It has been shown that bone
grafts taken from the jaws resorb more slowly thanother grafts.23,24 This might be due to the origin of
jawbones, which is membranous while other long bones
mainly are endochondral.23 Membranous bone has
been shown to form vascularization of the graft more
rapidly than does endochondral bone graft.25 Autogenous bone grafts are either cortical blocks, corticocancellous blocks, bone chips or compressed cancellous
bone cakes. The amount of bone needed can be predetermined using a surgical template to illustrate theamount of bone needed for implant placement. Suitable
intra-oral donor sites are symphysis, maxillary tuberosity, mandibular retromolar area, and zygoma. The
bone slurry produced during preparation of implant
bed can be harvested using suction-connected bonecollector.26–28 Contamination with oral bacteria ispossible during harvesting procedure but this risk isdecreased if harvesting is performed as aseptic as
possible.28

Fig. 1.2
6 mm.

Healing 6 month after grafting. Ridge dimension is now 5 toFig. 1.3

Implant of 4.1 mm of diameter after placement.

Figs. 1.1 to 1.3 Autologous bone harvesting from intra-oral site forhorizontal ridge augmentation before implant placement.

174

Brugnami F and Calefﬁ C: Implant site development

Augmentation with Allogenic, Xenogenic orAlloplastic Graft Materials

Fig. 2.1 Extraction socket. Reproduced by permission of Quintessence Publishing Co, Inc.

Allogenic bone material has been extensively used inbone regeneration (Figs. 2.1 to 2.3). Although somedoubts have been raised on its biological effects12 allogenic material may represent a valid alternative toautologous bone graft.13,14 Extensive research has
been focused on the development of bone substitutes.
Many of these products are based on minerals, which
are found in bone.26 Hydroxyl apatite (HA) is the major bone mineral. It can be also manufactured industrially. HA is non-resorbable while other coral-derived
materials are gradually resorbed.28,29 Coral granules
obtained from natural coral skeletons will be completely resorbed and replaced by host bone27 and havebeen used in bone augmentation procedures.28 Allogenic and xenogenic bone products might be abandoned in the future due to the risk of transmitting diseases. Allogenic, xenogenic and alloplastic materials
can be mixed with bone chips and thus decrease theamount of bone graft needed, which in this case can be
harvested from intra-oral sites.26
Guided Bone Regeneration

Guided Bone Regeneration (GBR) is a techniquein which bone growth is enhanced by maintaining thespace and preventing soft tissue in growth into the area
utilizing either a resorbable or non-resorbable barrier
membrane. GBR may be performed in conjunction withthe placement of the implants or during a surgicalintervention prior to implant placement. The staged
Fig. 2.2 Socket ﬁlled with DFDBA. Reproduced by permission of approach is primarily chosen in situations with large
Quintessence Publishing Co, Inc.
bone defects or in esthetic situation, to allow positioning of the implants in the prosthetically desired position. Hence, the alveolar ridge is augmented in a ﬁrst
surgical intervention. After the appropriate time forhealing, the implants are then placed into a site of sufﬁcient bone volume (Figs. 3.1, 3.2). Although autologous bone would be normally the material of choice,in a recent clinical study also a de-proteinized bovinebone mineral was applied in conjunction with abioresorbable collagen membrane.31 Metallic membranes32 or membranes supported by titanium
frame33–35 have been tested. Acellular matrix has beenused as a barrier membrane with demineralized freezedried bone allograft.36 Membranes in general are acontroversial issue in implantology and their use is atleast very technique sensitive.37 Non-resorbable membranes need a second operation for their removal andresorbable membranes can enhance inﬂammation.38
Fig. 2.3 4 months later after implant placement.
Intact periosteum or split palatal gingival ﬂaps are
Figs. 2.1 to 2.3 Allogeneic bone graft (DFDBA) before implant regarded by some authors as natural membranes.39
Still, however, good results with augmentation proceplacement.

Keio J Med 2005; 54 (4): 172–178

Fig. 3.1 Radiograph of same defect after GBR. Note Titanium
Membrane and pins.
Figs. 3.1 to 3.2

175

Fig. 3.2 Radiograph after 9 months. Note complete resolution ofvertical bone defect.

GBR with e-PTFE membrane. In this case Vertical Augmentation with Titanium reinforced membrane and pins.

dures using membranes have been presented.34,35,40–42
Vertical increase of a narrow alveolar crest has beenshown to be possible with membranes.34 Membranes
are often accompanied with bone grafts beneath them.43
Also, here autogenous bone chips are superior to demineralized allogenic grafts.
Bone Expansion and Split Crest Techniques
Alveolar reconstruction or alveolar widening withosteotomes and chisels produces a greenstick fractureleaving the remaining periosteum attached to the bone.
This periosteally pedicled buccal cortex is repositioned
and a new implant bed is created without even drilling.
The major beneﬁt of crestal widening is that the thinalveolar bone can be utilized for implantation without
grafting and the implants placed simultaneously withthe bone expansion procedure. One of the problems is
generally to assure precise positioning of implants
according to prosthetic needs. Since the expansion
is achieved by transposition of the buccal plate evenmore buccally, the implants may have a tendency to be
inclined too much in the same direction. Grafting between the fractured cortical lamellae is better integrated and opening of marrow space improves vascularization and healing.8 The direction of forces by chisels
should be aimed palatally to decrease the damageexerted on the fragile buccal plate. The bone can be
ﬂexed to some extent due to its elasticity.4 Bone compression is also achieved as well as an increase in thedensity of trabeculocity in the adjacent site.45 The
resulting gap can be covered by non-resorbable membrane46,8 and ﬁlled with allogenic material.8 Interpositional autogenous bone grafts have been used to improve bony healing in the gap.5 Membranes do notnecessarily improve the prognosis.47 Lamellar cortical
splitting can be initiated with a diamond disc or burs
and ﬁnalized with osteotomes.19 Implants inserted inalveolar bone in which the width has been increased bymeans of lateral widening have been shown to givesuccess rate between 86 and 97%.19,47 This should be
regarded as a very acceptable result and is comparablewith implantation without bone augmentation.
Sinus Floor Augmentation Techniques
The sinus ﬂoor augmentation technique has been
extensively utilized in the last 20 years to successfullyincrease the dimensions of the posterior maxilla for
implant placement.48 This technique is based on theelevation of the Schneiderian membrane from the ﬂoorof the maxillary sinus and the introduction of a bone
graft or a bone substitute (Figs. 4.1 and 4.2). This procedure is technically demanding and involves manyfactors that might affect implant survival such as thetype of graft used for augmentation, the surgical technique and the type of implants.49 The osteotome technique was introduced to increase primary stability ofdental implants in the posterior maxilla.50–52 It is aprocedure that has been well established in clinicalroutine. With implant shaped instruments the trabecular bone is compressed laterally. Moreover, thealveolar ridge can be expanded and the sinus ﬂoor canbe elevated through a crestal approach.51–53
Vertical Bone Defects
The indications for vertical ridge augmentation include situations where the remaining bone height is too
small for proper anchorage of oral implants; unfavor-

176

Brugnami F and Calefﬁ C: Implant site development

Fig. 4.1

View of buccal window.
Figs. 4.1 and 4.2

Fig. 4.2

Same view after grafting procedure is completed.

Sinus lift procedure with buccal window approach.

able crown to implant ratios and unfavorable esthetic
outcomes will result from the lack of remaining hardand soft tissues (Figs. 2.1 to 2.3). Data from animal
experiments have clearly demonstrated that growth ofbone above the external borders of the skeleton was
possible using GBR.54–60 In the ﬁrst clinical study onvertical ridge augmentation in humans, a titaniumreinforced ePTFE membrane was used to cover
implants that were allowed to protrude up to 7 mmabove the crest.61 The results after 9 months of submerged healing showed bone formation reaching up to
4 mm above the previous border of the alveolar crest.
The remainder of the space between the newly
formed bone and the membrane was occupied by nonmineralized tissue. Within the area of the newly formed
bone, osseointegration of the implants had occurred asdemonstrated by histologic analysis of experimentally
retrieved test implants. In another study, six patientswere treated with titanium-reinforced membranes andautogenic bone collected in a suction ﬁlter.62 Twelve
months following membrane placement, an averagegain of 5 mm of vertical bone height was measured,reaching up to a maximum of 7 mm.
Soft Tissues Augmentation
Historically, soft tissue management and augmentation has been described to enhance esthetic of ﬁxed
bridge.63–65 Many techniques of soft tissue augmentation have been used longer before the implants wereroutinely used in the dental ofﬁces. These procedures
are extremely technique sensitive and present a variable success rate.63–65 Today these techniques are utilized in conjunction with hard tissue augmentation procedures in order to obtain a more predictable successrate and to optimize esthetic and functional results.17,19

Conclusions
To maximize functional and esthetic results, implants
should be placed accordingly to prosthetic needs anddesign. Due to bone resorption after extraction, ideal
placement of implants would be often impossible without prior hard and soft tissue augmentation. Several
techniques are available nowadays. Advantages anddisadvantages of these techniques are presented. Solution of each case requires customization and often
combination of these techniques. Thus a deep knowledge of these techniques will allow the surgeon toproperly select the right combination for prosthetic
needs and especially for the esthetic and function ofpatients.

References
1. 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: 462–473
2. Simion M, Jovanovic SA, Trisi P, Scarano A, Piattelli A: Verticalridge augmentation around dental implants using a membrane
technique and autogenous bone or allografts in humans. Int J
Periodontics Restorative Dent 1998; 18: 8–23
3. Lustmann J, Lewinstein I: Interpositional bone grafting technique to widen narrow maxillary ridge. Int J Oral Maxillofac
Implants 1995; 10: 568–577
4. de Wijs FL, Cune MS: Immediate labial contour restoration forimproved esthetics: a radiographic study on bone splitting in anterior single-tooth replacement. Int J Oral Maxillofac Implants
1997; 12: 686–696
5. Truhlar RS, Orenstein IH, Morris HF, Ochi S: Distribution ofbone quality in patients receiving endosseous dental implants. J
Oral Maxillofac Surg 1997; 55: 38–45
6. Drago CJ: Rates of osseointegration of dental implants with regard to anatomical location. J Prosthodont 1992; 1: 29–31

Keio J Med 2005; 54 (4): 172–178
7. Cawood JI, Howell RA: A classiﬁcation of the edentulous jaws.
Int J Oral Maxillofac Surg 1988; 17: 232–236
8. Engelke WG, Diederichs CG, Jacobs HG, Deckwer I: Alveolar
reconstruction with splitting osteotomy and microﬁxation of
implants. Int J Oral Maxillofac Implants 1997; 12: 310–318
9. Suhonen JT, Meyer BJ: Polylactic acid (PLA) root replica inridge maintenance after loss of a vertically fractured incisor.
Endod Dent Traumatol 1996; 12: 155–160
10. Yilmaz S, Efeoglu E, Kilic AR: Alveolar ridge reconstruction
and/or preservation using root form bioglass cones. J Clin
Periodontol 1998; 25: 832–839
11. Wiesen M, Kitzis R: Preservation of the alveolar ridge at implantsites. Periodontal Clin Investig 1998; 20: 17–20
12. Becker W, Becker BE, Caffesse R: A comparison of demineralized freeze-dried bone and autologous bone to induce bone formation in human extraction sockets. J Periodontol 1994; 65:
1128–1133
13. Brugnami F, Then PR, Moroi H, Leone CW: Histologic evaluation of human extraction sockets treated with demineralized
freeze-dried bone allograft (DFDBA) and cell occlusive membrane. J Periodontol 1996; 67: 821–825
14. Brugnami F, Then PR, Moroi H, Kabani S, Leone CW: GBR
in human extraction sockets and ridge defects prior to implant
placement: clinical results and histologic evidence of osteoblastic
and osteoclastic activities in DFDBA. Int J Periodontics Restorative Dent 1999; 19: 259–267
15. Lekholm U, Zarb GA: Patient selection and preparation. In:
Branemark PI, Zarb GA, Albrektsson T, editors. Tissue integrated prostheses. Osseointegration in clinical dentistry. Chicago: Quintessence; 1985
16. Breault LG, Shakespeare RC, Fowler EB: Enhanced ﬁxed prosthetics with a connective tissue ridge augmentation. Gen Dent
1999; 47: 618–622
17. Adriaenssens P, Hermans M, Ingber A, Prestipino V, Daelemans P, Malevez C: Palatal sliding strip ﬂap: soft tissue management to restore maxillary anterior esthetics at stage 2 surgery: aclinical report. Int J Oral Maxillofac Implants 1999; 14: 30–36
18. Fugazzotto PA, De Paoli S: Maintenance of regenerated bone
beneath pontics: preliminary clinical report of 43 sites. Int J Oral
Maxillofac Implants 1999; 14: 392–397
19. Studer S, Naef R, Scharer P: Adjustment of localized alveolar
ridge defects by soft tissue transplantation to improve mucogingival esthetics: a proposal for clinical classiﬁcation and an evaluation of procedures. Quintessence Int 1997; 28: 785–805
20. Marx RE: Clinical application of bone biology to mandibular
and maxillary reconstruction. Clin Plast Surg 1994; 21: 377–392
21. Salonen MA, Oikarinen KS, Raustia AM, Knuuttila M, Virtanen
KK: Clinical and radiologic assessment of possibilities for endosseous implants and osseointegrated prostheses in 55-year-old
edentulous subjects. Acta Odontol Scand 1994; 52: 25–32
22. Caminiti MF, Sandor GK, Carmichael RP: Quantiﬁcation of bone
harvested from the iliac crest using a power-driven trephine. J
Oral Maxillofac Surg 1999; 57: 801–805
23. Smith JD, Abramson M: Membranous vs endochondrial bone
autografts. Arch Otolaryngol 1974; 99: 203–205
24. Kusiak JF, Zins JE, Whitaker LA: The early revascularization of
membranous bone. Plast Reconstr Surg 1985; 76: 510–516
25. Oikarinen K, Kainulainen V, Kainulainen T: A method of harvesting corticocancellous bone chips for reconstructive maxillofacial surgery. Int J Oral Maxillofac Surg 1997; 26: 103–105
26. Jensen J, Sindet-Pedersen S: Autogenous mandibular bone
grafts and osseointegrated implants for reconstruction of the severely atrophied maxilla: a preliminary report. J Oral Maxillofac
Surg 1991; 49: 1277–1287
27. Young MP, Carter DH, Worthington H, Korachi M, Drucker
DB: Microbial analysis of bone collected during implant surgery:

177

28.

29.
30.

31.

32.

33.

34.

35.

36.

37.

38.

39.

40.

41.

42.

43.

44.

a clinical and laboratory study. Clin Oral Implants Res 2001; 12:
95–103Kainulainen V, Oikarinen K: Comparison of four bone collectors
designed for oral and maxillofacial surgery – an in vitro study.
Clin Oral Implants Res 1998; 9: 327–332
Zide MF: Autogenous bone harvest and bone compacting for
dental implants. Compend Contin Educ Dent 2000; 21: 585–590
Buser D, Dula K, Belser U, Hirt HP, Berthold H: Localized
ridge augmentation using guided bone regeneration. 1. Surgicalprocedure in the maxilla. Int J Periodontics Restorative Dent
1993; 13: 29–45
Zitzmann NU, Scharer P, Marinello CP, Schupbach P, Berglundh T: Alveolar ridge augmentation with Bio-Oss: a histologic
study in humans. Int J Periodontics Restorative Dent 2001; 21:
288–295
Lekovic V, Kenney EB, Weinlaender M, Han T, Klokkevold P,
Nedic M, Orsini M: A bone regenerative approach to alveolar
ridge maintenance following tooth extraction. Report of 10
cases. J Periodontol 1997; 68: 563–570
von Arx T, Cochran DL, Hermann JS, Schenk RK, Higginbottom FL, Buser D: Lateral ridge augmentation and implant
placement: an experimental study evaluating implant osseointegration in different augmentation materials in the canine mandible. Int J Oral Maxillofac Implants 2001; 16: 343–354
Lekholm U, Becker W, Dahlin C, Becker B, Donath K, Morrison E: The role of early versus late removal of GTAM membranes on bone formation at oral implants placed into immediate
extraction sockets. An experimental study in dogs. Clin Oral
Implants Res 1993; 4: 121–129
Lekovic V, Camargo PM, Klokkevold PR, Weinlaender M,
Kenney EB, Dimitrijevic B, Nedic M: Preservation of alveolarbone in extraction sockets using bioabsorbable membranes. J
Periodontol 1998; 69: 1044–1049
Linde A, Hedner E: Recombinant bone morphogenetic protein2 enhances bone healing, guided by osteopromotive e-PTFE
membranes: an experimental study in rats. Calcif Tissue Int
1995; 56: 549–553
Lorenzoni M, Pertl C, Keil C, Wegscheider WA: Treatment ofperi-implant defects with guided bone regeneration: a comparative clinical study with various membranes and bone grafts. Int J
Oral Maxillofac Implants 1998; 13: 639–646
Lorenzoni M, Pertl C, Polansky R, Wegscheider W: Guided
bone regeneration with barrier membranes – a clinical andradiographic follow-up study after 24 months. Clin Oral Implants
Res 1999; 10: 16–23
Chung CP, Kim DK, Park YJ, Nam KH, Lee SJ: Biologicaleffects of drug-loaded biodegradable membranes for guided
bone regeneration. J Periodontal Res 1997; 32: 172–175
Becker W, Becker BE, Polizzi G, Bergstrom C: Autogenous
bone grafting of bone defects adjacent to implants placed into
immediate extraction sockets in patients: A prospective study.
Int J Oral Maxillofac Implants 1994: 9: 389–396
Brunel G, Brocard D, Duffort JF, Jacquet E, Justumus P, Simonet T, Benque E: Bioabsorbable materials for guided bone regeneration prior to implant placement and 7-year follow-up: report of 14 cases. J Periodontol 2001; 72: 257–264
Lang NP, Bragger U, Hammerle CH, Sutter F: Immediatetransmucosal implants using the principle of guided tissue regeneration. I. Rationale, clinical procedures and 30-monthresults. Clin Oral Implants Res 1994; 5: 154–163
Lundgren AK, Lundgren D, Sennerby L, Taylor A, Gottlow J,
Nyman S: Augmentation of skull bone using a bioresorbablebarrier supported by autologous bone grafts. An intra-individual
study in the rabbit. Clin Oral Implants Res 1997; 8: 90–95
Summers RB: A new concept in maxillary implant surgery: theosteotome technique. Compendium 1994; 15: 152, 154–156

178
45. Burchardt H: The biology of bone graft repair. Clin Orthop
Relat Res 1983; 174: 28–42
46. Ashman A: Postextraction ridge preservation using a synthetic
alloplast. Implant Dent 2000; 9: 168–176
47. Sethi A, Kaus T: Maxillary ridge expansion with simultaneous
implant placement: 5-year results of an ongoing clinical study.
Int J Oral Maxillofac Implants 2000; 15: 491–499
48. Boyne PJ, James RA: Grafting of the maxillary sinus ﬂoor withautogenous marrow and bone. J Oral Surg 1980; 38: 613–616
49. Wallace SS, Froum SJ: Effect of maxillary sinus augmentation on
the survival of endosseous dental implants. A systematic review.
Ann Periodontol 2003; 8: 328–343
50. Summers RB: The osteotome technique: Part 2 – The ridge expansion osteotomy (REO) procedure. Compendium 1994; 15:422, 424, 426
51. Summers RB: The osteotome technique: Part 3 – Less invasive
methods of elevating the sinus ﬂoor. Compendium 1994; 15: 698,
700, 702–704
52. Summers RB: The osteotome technique: Part 4 – Future site
development. Compend Contin Educ Dent 1995; 16: 1080, 1092
53. Summers RB: Sinus ﬂoor elevation with osteotomes. J Esthet
Dent 1998; 10: 164–171
54. Hammerle CH, Olah AJ, Schmid J, Fluckiger L, Gogolewski S,
Winkler JR, Lang NP: The biological effect of natural bonemineral on bone neoformation on the rabbit skull. Clin Oral
Implants Res 1997; 8: 198–207
55. Kostopoulos L, Karring T: Augmentation of the rat mandibleusing guided tissue regeneration. Clin Oral Implants Res 1994; 5:
75–82
56. Kostopoulos L, Karring T, Uraguchi R: Formation of jawbone
tuberosities by guided tissue regeneration. An experimental
study in the rat. Clin Oral Implants Res 1994; 5: 245–253

Brugnami F and Calefﬁ C: Implant site development
57. Lundgren AK, Lundgren D, Sennerby L, Taylor A, Gottlow J,
Nyman S: Augmentation of skull bone using a bioresorbablebarrier supported by autologous bone grafts. An intra-individual
study in the rabbit. Clin Oral Implants Res 1997; 8: 90–95
58. Lundgren D, Lundgren AK, Sennerby L, Nyman S: Augmentation of intramembraneous bone beyond the skeletal envelope
using an occlusive titanium barrier. An experimental study in the
rabbit. Clin Oral Implants Res 1995; 6: 67–72
59. Schmid J, Hammerle CH, Stich H, Lang NP: Supraplant, a novel
implant system based on the principle of guided bone generation. A preliminary study in the rabbit. Clin Oral Implants Res
1991; 2: 199–202
60. Schmid J, Hammerle CH, Fluckiger L, Winkler JR, Olah AJ,
Gogolewski S, Lang NP: Blood-ﬁlled spaces with and without
ﬁller materials in guided bone regeneration. A comparative experimental study in the rabbit using bioresorbable membranes.
Clin Oral Implants Res 1997; 8: 75–81
61. Simion M, Trisi P, Piattelli A: Vertical ridge augmentation using
a membrane technique associated with osseointegrated implants.
Int J Periodontics Restorative Dent 1994; 14: 496–511
62. Tinti C, Parma-Benfenati S, Polizzi G: Vertical ridge augmentation: what is the limit? Int J Periodontics Restorative Dent 1996;
16: 220–229
63. Seibert JS: Reconstruction of the partially edentulous ridge:
gateway to improved prosthetics and superior aesthetics. Pract
Periodontics Aesthet Dent 1993; 5: 47–55
64. Seibert JS: Ridge augmentation to enhance esthetics in ﬁxed
prosthetic treatment. Compendium 1991; 12: 548, 550, 552
passim
65. Kaldahl WB, Tussing GJ, Wentz FM, Walker JA: Achieving anesthetic appearance with a ﬁxed prosthesis by submucosal grafts.
J Am Dent Assoc 1982; 104: 449–452