Clinical outcomes of sinus floor augmentation for implant placement using autogenous bone or bone substitutes: a systematic review

Authors


  • Conflicts of interest:
    The authors declare no conflicts of interest.

Correspondence to:
Prof. Dr. Dr. Emeka Nkenke
Department of Oral and Maxillofacial Surgery
University Hospital of Erlangen
Glueckstr 11
91054 Erlangen
Germany
Tel.: +49 9131 8533653
Fax: +49 9131 8534219
e-mail: emeka.nkenke@uk-erlangen.de

Abstract

Background: To date, there are still no clear cut guidelines for the use of autogenous bone or bone substitutes.

Aim: The aim of the present review was to analyze the current literature in order to determine whether there are advantages of using autogenous bone (AB) over bone substitutes (BS) in sinus floor augmentation. The focused question was: is AB superior to BS for sinus floor augmentation in partially dentate or edentulous patients in terms of implant survival, patient morbidity, sinusitis, graft loss, costs, and risk of disease transmission?

Materials and methods: The analysis was limited to titanium implants with modified surfaces placed in sites with 6 mm of residual bone height and a lateral wall approach to the sinus. A literature search was performed for human studies focusing on sinus floor augmentation.

Results: Twenty-one articles were included in the review. The highest level of evidence consisted of prospective cohort studies. A descriptive analysis of the constructed evidence tables indicated that the type of graft did not seem to be associated with the success of the procedure, its complications, or implant survival. Length of healing period, simultaneous implant placement or a staged approach or the height of the residual alveolar crest, sinusitis or graft loss did not modify the lack of effect of graft material on the outcomes. Three studies documented that there was donor site morbidity present after the harvest of AB. When iliac crest bone was harvested this sometimes required hospitalization and surgery under general anesthesia. Moreover, bone harvest extended the operating time. The assessment of disease transmission by BS was not a topic of any of the included articles.

Discussion and Conclusion: The retrieved evidence provides a low level of support for selection of AB or a bone substitute. Clear reasons could not be identified that should prompt the clinician to prefer AB or BS.

Sinus floor augmentation is a technique based on the elevation of the sinus membrane from the floor of the maxillary sinus. Various graft materials have been used to fill the newly formed space. Autogenous bone (AB), allografts, xenografts, alloplastic materials, and mixtures of various materials have been proposed for this purpose (Wheeler 1997).

AB is very popular for sinus floor augmentation, because it possesses osteoconductive, osteoinductive, and osteogenic properties (Galindo-Moreno et al. 2008). Unfortunately, the harvest of AB requires donor site surgery and potentially increases patient morbidity (Nkenke et al. 2001, 2002, 2004). In this context, it is important to note that maxillary sinus floor augmentation is an elective procedure. In such kind of surgery, it should always be a priority to reduce patient morbidity to a minimum. It has been clearly stated that donor site morbidity cannot be ignored when AB is used for maxillary sinus floor augmentation (Kübler et al. 1999; Raghoebar et al. 1999).

Harvesting AB from intraoral sites can be associated with a number of problems like devitalization of anterior mandibular teeth by involvement of tooth apices, changes in facial esthetics, possible damage to mental and lower dental nerves, and increased risk of mandibular ramus fracture when intraoral donor sites are chosen (Galindo-Moreno et al. 2007). Bone harvest from extraoral sites may cause hemorrhage, instability of the sacro-iliac joint, hernia through the donor site, adynamic ileus, or gait disturbances (Kalk et al. 1996). As a consequence, the use of AB for sinus floor augmentation has been questioned (Tadjoedin et al. 2002).

Therefore, it was the aim of the present review to determine whether there are advantages in using AB over bone substitutes (BS) for sinus floor augmentation. The question focused on was: is AB superior to BS for sinus floor augmentation in partially dentate or edentulous patients in terms of implant survival, patient morbidity, sinusitis, graft loss, costs, and risk of disease transmission?

Materials and methods

Search strategy

A systematic search strategy was used. In the initial phase of the review, a computerized literature search for human studies was performed (Medline and Embase databases, 1 January 1966–31 December 2008). There was no language restriction.

In addition, a hand search was carried out in Annals of Periodontology, British Journal of Oral and Maxillofacial Surgery, Clinical Implant Dentistry & Related Research, Clinical Oral Implants Research, Dental Clinics of North America, Implant Dentistry, The International Journal of Oral and Maxillofacial Surgery, International Journal of Periodontics and Restorative Dentistry, International Journal of Prosthodontics, Journal of Clinical Periodontology, Journal of Cranio-Maxillofacial Surgery, Journal of Oral Implantology, Journal of Oral and Maxillofacial Surgery, Journal of Periodontology, Journal of Prosthetic Dentistry, Journal of the American Dental Association, Mund-, Kiefer- und Gesichtschirurgie, Oral and Maxillofacial Surgery, Oral Surgery Oral Medicine Oral Pathology, Periodontology 2000, Scandinavian Journal of Plastic and Reconstructive Surgery, and The International Journal of Oral & Maxillofacial Implants.

Moreover, the Cochrane Controlled Trials Register and The Cochrane Health Group Specialized Register were checked for publications on sinus floor augmentation.

The full text of reviews was obtained from reviews on sinus floor augmentation published between 1 January 1998 and 31 December 2008. Additional publications were identified from the reference lists of the retrieved articles.

Search terms

Keywords were ‘sinus augmentation’ OR ‘sinus floor augmentation’ OR ‘sinus floor elevation’ OR ‘sinus grafting’ OR ‘sinus lift’. The search was limited to ‘human trial’ (MeSH term, clinical studies). Additionally, the MeSH terms ‘clinical trial’, ‘comparative study’, ‘controlled clinical trial’, ‘randomized controlled trial’, ‘meta-analysis’, and ‘review’ were used.

Inclusion criteria

The inclusion criteria for study selection were:

  •  (i)clinical studies,
  • (ii)lateral window approach to the sinus,
  • (iii)elevation of sinus mucosa,
  •   (iv)use of an augmentation material,
  • (v)use of root-form or cylindrical titanium implants with modified surfaces,
  •  (vi)studies with a follow-up interval of at least 12 months after functional loading of the implants placed in the region of the sinus floor augmentation,
  • (vii)average residual height of pristine bone in the region of sinus floor augmentation of a maximum of 6 mm,
  • (viii)defined survival or success criteria for the implants placed in the region of the sinus floor augmentation,
  •  (xi)documentation of the implant survival rate after a defined period of time, and
  •  (x)a sample size of at least 10 patients.

Exclusion criteria

Publications dealing with in vitro studies or preclinical (animal) studies were excluded. Human studies not meeting all inclusion criteria were also excluded from the review:

In addition, studies were excluded if

  •  (i)additional augmentation procedures were carried out besides sinus floor augmentation,
  • (ii)survival rates or success rates could not be distinguished for rough- and smooth-surfaced implants,
  • (iii)they reported on the same patient cohort, and
  • (iv)personal communication was included in the paper.

Selection of studies

Titles derived from this broad search were independently screened by the two authors based on the inclusion criteria. Disagreements were resolved by discussion. Following this, abstracts of all titles agreed on by both authors were obtained and screened for meeting the inclusion criteria. If no abstract was available in the database, the abstract of the printed article was used. The selected articles were then obtained in full text. If the title and abstract did not provide sufficient information regarding the inclusion criteria, the full report was obtained as well. Again, disagreements were resolved by discussion.

Finally, the selection based on inclusion and exclusion criteria was made for the full-text articles. For this purpose, Material and Methods and Results of these studies were screened. This step was again carried out independently by the two authors. Disagreements were resolved by discussion (Fig. 1).

Figure 1.

 Search strategy: sinus floor augmentation by a lateral approach.

Data extraction

Two reviewers independently extracted the data using data extraction tables. Any disagreements were resolved by double-checking the original data and by discussion. From the selected papers, data were extracted on author(s), year of publication, study design, total number of patients, inclusion and exclusion criteria, follow-up period, patients lost to follow-up, healing period, simultaneous implant placement or staged approach, height of residual alveolar crest, sinus mucosa perforation, operating time, sinusitis, graft loss, patient morbidity, disease transmission, and costs.

All abbreviations used in the text are given in Table 1.

Table 1. Abbreviations used in the text
AbbreviationFull text
ABAutogenous bone
β-TCPβ-tri-calcium phosphate
BSBone substitutes
BSEBovine spongiform encephalopathy
CIConfidence interval
CJDCreutzfeldt–Jakob disease
DBBMDeproteinized bovine bone mineral
DFDBADemineralized freeze-dried bone allograft
HAHydroxyapatite
ICBIrradiated cancellous bone
MBCPMacroporous biphasic calcium phosphate
PCCSProspective comparative case series
PCSProspective case series
PRPPlatelet rich plasma
RCCSRetrospective comparative case series
RCSRetrospective case series
VCJDNew variant Creutzfeldt–Jakob disease

Results

Study characteristics

By the electronic literature search, a total of 1028 titles were identified. Twenty-one original articles fulfilled the inclusion criteria (Fig. 1). The studies with the highest level of evidence were prospective cohort studies (Table 2).

Table 2. Study design and basic patient data
AuthorsDesign
of study
Patients
Number of
patients (n)
Age range
(years)
Mean age
(years)
Residual bone
height (mm)
  1. NS, not specified; PCCS, prospective comparative case series; PCS, prospective case series; RCCS, retrospective comparative case series; RCS, retrospective case series.

Kim et al. (2009)RCCS28NSNS4.5
Kahnberg & Vannas-Löfqvist (2008)PCS36NS605–6
Lee et al. (2008)PCCS5230–7350<6
Galindo-Moreno et al. (2007)PCS70NSNS≥5/<5
Krennmair et al. (2007)RCS3737–66NS3.5
Marchetti et al. (2007)PCS3023–6748.85.3/2.5
Karabuda et al. (2006)PCS9129–7446≥5/<5
Lindenmüller & Lambrecht (2006)RCCS8018–82574.5/2.4
Peleg et al. (2006)PCS73142–81531–5
Hallman & Nordin (2004)RCS5023–8261<5
Iturriaga & Ruiz (2004)RCS58NSNS<5
Mazor et al. (2004)PCS10525–6951<5
Peleg et al. (2004)PCCS156NSNS≤5
Engelke et al. (2003)PCS8327–8655.65.8
Stricker et al. (2003)PCS4138–7355≥5/<5
Valentini & Abensur (2003)RCCS59NSNS≥5/<5
van den Bergh et al. (2000)PCS2432–6550<4
Kaptein et al. (1998)RCS7736–7651<5
van den Bergh et al. (1996)PCS4222–6444<4
Watzek et al. (1998)RCCS2043–7653.22.1
Zinner & Small (1996)PCS5030–71NS<5

Exclusion of studies

The reasons for excluding studies after the full text was obtained were a sample size of <10 patients (15 articles), not reporting on sinus floor augmentation (three articles), additional augmentation procedures (two articles), surgical technique other than a lateral approach (36 articles), no implant survival data (33 articles), no information on the residual height of the alveolar crest before surgery (25 articles), a mean bone level >6 mm before surgery (nine articles), <1 year of follow-up (seven articles), <1 year of functional loading of implants (four articles), multiple publications on the same patient cohorts (12 articles), titanium implants without modified surfaces or surfaces not specified (24 articles), and implant survival rates not distinguishable for implants with modified surfaces and implants with other surfaces (three articles) (Fig. 1).

Included studies

Twenty-one articles were selected for inclusion in a narrative review. They are presented in Tables 2–8. Fourteen studies reported inclusion and exclusion criteria for their patients. Most often, patients with a history of sinusitis, immune system disorders, and uncontrolled systemic diseases were excluded. While most of the studies excluded smokers, they were explicitly included in two studies (Table 3). The exclusion criteria did not differ for augmentation procedures with AB or BS.

Table 3. Exclusion criteria
AuthorsExclusion criteria
SmokersSystemic
disease
Immune
deficiency
Diabetes
mellitus
Sinus
pathology
Radio-/chemotherapyPeriodontitisOthers
  1. NS, not specified; EX, excluded.

Kim et al. (2009)NSNSNSNSNSNSNSNS
Kahnberg & Vannas-Löfqvist (2008)EXEXNSNSNSNSNSNS
Lee et al. (2008)NSNSNSNSEX: acute sinusitisNSNSNS
Galindo-Moreno et al. (2007)IncludedEX: uncontrolled systemic diseaseNSNSEX: history of chronic sinusitisNSNSEX: allergies with respiratory component
Krennmair et al. (2007)NSNSNSNSNSNSNSNS
Marchetti et al. (2007)IncludedNSEXEXNSEXNSEX: history of drug abuse
Karabuda et al. (2006)EXNSEXEX: uncontrolled diabetes mellitusEX: history of chronic sinusitisEX: ongoing radio- and chemotherapyNSNS
Lindenmüller & Lambrecht (2006)NSNSNSEX: uncontrolled diabetes mellitusEX: sinusitis/previous sinus surgeryEX: radiotherapyNSEX: cysts/tumors in head and neck area
Peleg et al. (2006)NSNSEXNSEXEX: previous radiotherapyNSNS
Hallman & Nordin (2004)NSEX: severe systemic diseaseNSEX: uncontrolled diabetes mellitusNSEX: history of radiotherapy in head and neck areaEXNS
Iturriaga & Ruiz (2004)NSNSNSNSNSNSNSNS
Mazor et al. (2004)NSNSNSNSNSNSNSNS
Peleg et al. (2004)NSNSNSNSNSNSNSNS
Engelke et al. (2003)NSEXNSNSEX: sinusitisNSEX: untreated periodontitisNS
Stricker et al. (2003)NSNSEXEX: uncontrolled diabetes mellitusNSEX: ongoing radio- and chemotherapyNSEX: history of drug abuse
Valentini & Abensur (2003)EXNSNSNSNSNSNSNS
van den Bergh et al. (2000)NSEXEXNSEXNSNSEX: alcoholism, history of endocarditis heart valve prosthesis metallic joint prosthesis
Kaptein et al. (1998)NSNSNSNSNSNSNSNS
van den Bergh et al. (1996)NSEXEXNSEXNSNSEX: alcoholism, history of endocarditis heart valve prosthesis metallic joint prosthesis
Watzek et al. (1998)NSNSNSNSEXNSNSNS
Zinner & Small (1996)NSNSNSNSNSNSNSNS
Table 4. Characteristics of surgical procedures
AuthorsCharacteristics of surgical procedures
Simultaneous implant
placement/staged
approach
AntibioticsSurgical
approach
Membrane
coverage of
lateral window
Mean
follow-up
(month)
Lost to
follow-up (%)
  • *

    Min/max; no mean value given.

  • NS, not specified.

Kim et al. (2009)Simultaneous/stagedNSAccess holeResorbable120
Kahnberg & Vannas-Löfqvist (2008)StagedNSTrap doorNo340
Lee et al. (2008)Simultaneous/stagedNSAccess holeResorbable120
Galindo-Moreno et al. (2007)Simultaneous/stagedPre/postAccess holeResorbable24NS
Krennmair et al. (2007)StagedNSAccess holeResorbable440
Marchetti et al. (2007)Simultaneous/stagedPre/postTrap doorNo60NS
Karabuda et al. (2006)Simultaneous/stagedPre/postTrap doorResorbable367.7
Lindenmüller & Lambrecht (2006)Simultaneous/stagedPostNSNo241.5
Peleg et al. (2006)SimultaneousPre/postTrap doorResorbable1081.8
Hallman & Nordin (2004)StagedPre/postNSNo190
Iturriaga & Ruiz (2004)StagedNSTrap doorNo12NS
Mazor et al. (2004)SimultaneousPre/postAccess holeResorbable22NS
Peleg et al. (2004)StagedPre/postNsResorbable16NS
Engelke et al. (2003)Simultaneous/stagedPostAccess holeNo12NS
Stricker et al. (2003)Simultaneous/stagedNoTrap doorNo27.40
Valentini & Abensur (2003)Simultaneous/stagedPre/postTrap doorNo73.21.7
van den Bergh et al. (2000)StagedPre/postTrap doorNo12–72*0
Kaptein et al. (1998)StagedPre/postTrap doorNo55NS
van den Bergh et al. (1996)StagedPre/postTrap doorNo12–72*0
Watzek et al. (1998)StagedPre/postTrap doorNo54NS
Zinner & Small (1996)SimultaneousPre/postTrap doorResorbable60NS
Table 5. Healing periods
AuthorsHealing periods
Simultaneous implant
placement
Staged approach
Implant placement –
stage 2 surgery
(months)
Bone grafting
– implant
placement
(months)
Implant
placement –
stage 2 surgery
(months)
  1. AB, autogenous bone; BS, bone substitute; NS, not specified.

Kim et al. (2009)NS4–7NS
Kahnberg & Vannas-Löfqvist (2008)4–56
Lee et al. (2008)NS3–13NS
Galindo-Moreno et al. (2007)NS6–8NS
Krennmair et al. (2007)6–9NS
Marchetti et al. (2007)555
Karabuda et al. (2006)NS6NS
Lindenmüller & Lambrecht (2006)7.7 (mean)10.3 (mean)9.2 (mean)
Peleg et al. (2006)6–9
Hallman & Nordin (2004)6–11 (mean)0.3–10
Iturriaga & Ruiz (2004)3–115–9
Mazor et al. (2004)6
Peleg et al. (2004)4–8
Engelke et al. (2003)NS6–12NS
Stricker et al. (2003)4.6 (mean)4.9 (mean)3.9 (mean)
Valentini & Abensur (2003)966
van den Bergh et al. (2000)64
Kaptein et al. (1998)3.4 (mean)4 (mean)
van den Bergh et al. (1996)44
Watzek et al. (1998)3–8 (AB)
6 (BS)
6
Zinner & Small (1996)9
Table 6. Grafting materials and implant types
AuthorsGrafting materialImplants
  1. AB, autogenous bone; DBBM, deproteinized bovine bone mineral; DFDBA, demineralized freeze-dried bone allograft; HA, hydroxyapatite; β-TCP, β-tri-calcium phosphate; PRP, platelet rich plasma; MBCP, macroporous biphasic calcium phosphate; ICB, irradiated cancellous bone.

Kim et al. (2009)AB+DBBM/AB+Allograft+DBBMOsstem Implant
Kahnberg & Vannas-Löfqvist (2008)AB (iliac/mand)/AB+DBBMTioblast ST Implants
Lee et al. (2008)MBCP/MBCP+ICB/MBCP+ABTiUnite, ITI
Galindo-Moreno et al. (2007)AB+DBBM+PRPAstra, Microdent
Krennmair et al. (2007)AB+DBBMFrialit 2, Camlog
Marchetti et al. (2007)70% AB+30% DBBMFrialit 2
Karabuda et al. (2006)DBBM+fully synthetic ceramic graftCamlog, Xive, MIS
Lindenmüller & Lambrecht (2006)AB/Ceros 82/AG+Ceros 82/Algipore/AG+AlgiporeITI, Frialit 2
Peleg et al. (2006)AB/50% AB+50%DBBM/DFDBA/bone cementZimmer Dental
Hallman & Nordin (2004)DBBM+fibrin glueITI
Iturriaga & Ruiz (2004)AB (calvarium)Astra, 3i Osseotite, Corevent, Semados
Mazor et al. (2004)AB+DBBM+PRPZimmer Dental
Peleg et al. (2004)AB/50%AB+50% DBBMZimmer Dental
Engelke et al. (2003)AB+β-TCPFrialit 2, IMZ, Pitt-easy, ITI
Stricker et al. (2003)AB (iliac)ITI
Valentini & Abensur (2003)50% DFDBA+50% DBBM/DBBMIMZ
van den Bergh et al. (2000)DFDBAITI
Kaptein et al. (1998)AB (iliac block)+AB (particulated)+HAIMZ
van den Bergh et al. (1996)AB (iliac particulate)ITI
Watzek et al. (1998)AB (iliac)/AB (iliac)+HA or DBBM/AB (iliac or oral cavity)+HA+DBBMIMZ, Frialit 2
Zinner & Small (1996)AB+DFDBA+HAITI
Table 7. Complications accompanying sinus floor augmentation
AuthorsComplications (%)
Membrane
perforation
Postoperative
sinusitis
Partial graft
failure
Total graft
failure
  1. NS, not specified.

Kim et al. (2009)28.610.7NSNS
Kahnberg & Vannas-Löfqvist (2008)NS22.211.10
Lee et al. (2008)8.60NSNS
Galindo-Moreno et al. (2007)0000
Krennmair et al. (2007)58NSNSNS
Marchetti et al. (2007)0NSNSNS
Karabuda et al. (2006)13.2NSNSNS
Lindenmüller & Lambrecht (2006)11.23.100
Peleg et al. (2006)NSNS250
Hallman & Nordin (2004)14.12.8NSNS
Iturriaga & Ruiz (2004)32.82.602.6
Mazor et al. (2004)NSNSNSNS
Peleg et al. (2004)NS000
Engelke et al. (2003)23.70.80.80
Stricker et al. (2003)37.90NSNS
Valentini & Abensur (2003)NS1.3NSNS
van den Bergh et al. (2000)20NSNSNS
Kaptein et al. (1998)16NSNSNS
van den Bergh et al. (1996)4.81.6NSNS
Watzek et al. (1998)10NSNSNS
Zinner & Small (1996)NSNSNSNS
Table 8. Implant survival rates
AuthorsImplant survival rates (%)
Over allABBSAB+BSSimultaneous
placement
Staged
approach
Membrane
coverage
No membrane
coverage
  1. AB, autogenous bone; BS, bone substitute; NS, not specified.

Kim et al. (2009)89.4  89.393.7583.389.3 
Kahnberg & Vannas-Löfqvist (2008)100100   100 100
Lee et al. (2008)98.46NSNSNSNSNS98.46 
Galindo-Moreno et al. (2007)99  9999.597.999 
Krennmair et al. (2007)100  100100100 
Marchetti et al. (2007)96.3  94.987.597.2 94.9
Karabuda et al. (2006)95.9 95.10 NSNSNSNS
Lindenmüller & Lambrecht (2006)90NSNSNS91.782NSNS
Peleg et al. (2006)97.9NSNSNS97.9 97.9 
Hallman & Nordin (2004)94.5 94.5  94.5NSNS
Iturriaga & Ruiz (2004)100100   100NSNS
Mazor et al. (2004)100  100100 100 
Peleg et al. (2004)9898.6 97.3 9898 
Engelke et al. (2003)94.8  94.897.780.6NSNS
Stricker et al. (2003)99.599.5  NSNSNSNS
Valentini & Abensur (2003)97.8 94.5 87.397.7NSNS
van den Bergh et al. (2000)100 100  100NSNS
Kaptein et al. (1998)88.2  88.2 88.2 88.2
van den Bergh et al. (1996)100100   100NSNS
Watzek et al. (1998)95.494.410095.4 95.4NSNS
Zinner & Small (1996)98.6  98.698.6 NSNS

Patients lost to follow-up were documented in 12 studies (Table 4).

The approach to the sinus through the lateral antral wall was either performed by a trap door technique (13 studies) or by the preparation of an access hole by removal of the buccal bone plate (six studies) (Table 4). In three studies, the approach was not reported in detail.

In 10 studies, groups with sinus floor augmentation and simultaneous implant placement and groups with a staged approach were included. In these studies, the decision on the use of one or the other technique was based on the height of the residual crestal bone beyond the sinus. In eight studies, a staged approach was used exclusively, while in four studies only sinus floor augmentation with simultaneous implant placement was performed (Table 5). No differences were detectable for implant survival rates for the different graft materials that were associated by simultaneous or staged implant placement.

A wide variety of sources for AB were used. AB from the chin, the mandibular ramus, the calvarium, and the iliac crest was included. In 16 studies, AB was combined with a bone substitute. In seven studies patient groups were included, where sinus floor augmentation was carried out with BS alone. The combination of autogenous bone with fibrin glue or PRP was also reported (Table 6). The use of membranes for the coverage of the lateral window and the prescription of antibiotics are outlined in Table 3. The use of membranes did not seem to influence implant survival in dependence of the graft material used.

Sinus membrane perforation was the most frequently reported complication. It ranged from 0% to 58% of the cases. Acute sinusitis was found during the postoperative course in a range of 0–22%. Partial graft loss was found in 0–25% of the cases. Total graft loss occurred in up to 2.6% of the cases. Neither sinusitis, partial graft loss, or total graft loss could be attributed to a specific graft material (Table 7).

Donor site morbidity was specified in three studies (Watzek et al. 1998; Iturriaga & Ruiz 2004; Marchetti et al. 2007). Harvesting of bone from the iliac crest led to donor site morbidity within the first two postoperative weeks (Marchetti et al. 2007). Donor site infections were found after harvest of mandibular ramus grafts. Hematomas, penetration into the cranial cavity, and minimal patches of alopecia were found after harvest of calvarial bone (Iturriaga & Ruiz 2004). The volume of harvested AB was assessed in only one study (Peleg et al. 2004).

Healing periods after simultaneous implant placement ranged from 2 to 10 months. In staged approaches, healing periods for the graft material from 3 to 13 months were chosen. After implant placement additional healing periods of up to 10 months were reported (Table 5). The length of the healing periods did not seem to influence implant survival in dependence of the graft material used.

The implant survival rate was not influenced by the use of AB alone or BS for sinus floor augmentation. When combinations of different graft materials were used, the implant survival rate for >12 months of follow-up under functional loading exceeded 90% for most of the studies (Table 8). Only in one study was the influence of smoking on implant survival assessed (Lindenmüller & Lambrecht 2006). In smokers, the implant survival rate was 85.4% compared with 93.3% in non-smokers after 2 years. However, the survival data were not specified for the different graft materials. None of the studies examined whether systemic diseases or other risk factors had an influence on implant survival in dependence of the different graft materials used.

From the studies included in the review no clear trend could be derived concerning the aspect whether sinus floor augmentation and simultaneous implant placement or a staged approach should be preferred as far as implant survival is concerned (Table 8).

The resorption of the graft material over time was documented in some of the studies (Hallman & Nordin 2004; Kim et al. 2009). Graft resorption did not seem to influence implant survival in dependence of the graft material used.

None of the studies that used allogenic or xenogenic material was designed to report on the transmission of infectious diseases. Cases of disease transmission were not documented in any of the studies.

The aspect of cost was not explicitly treated in any of the studies. However, it was reported that bone harvesting led to an extension of operating time of up to 15 min, when intraoral donor sites were chosen (Peleg et al. 2004). Moreover, it was mentioned that surgery was carried out under general anesthesia when iliac crest bone was harvested and that patients were hospitalized up to 5 days after this procedure (Marchetti et al. 2007).

Discussion

Sinus floor augmentation is one of the most reliable procedures in preprosthetic surgery. A number of systematic reviews and meta-analyses have been performed on this topic (Table 9). These reviews have shown that titanium implants without modified surfaces performed significantly worse than implants with modified surfaces when placed following sinus floor augmentation. Therefore, implants without modified surfaces were excluded from the present review. Based on this major change compared with the previous reviews, the aim to determine whether there are advantages in using AB compared with BS for sinus floor augmentation. The question focused on was: is AB superior to BS for sinus floor augmentation in partially dentate or edentulous patients in terms of implant survival, patient morbidity, sinusitis, graft loss, costs, and risk of disease transmission?

Table 9. Systematic reviews and meta-analyses on sinus floor augmentation
AuthorsNumber of studies
included (n)
Surgical approach
to sinus
Maximum follow-up
period (month)
Implant survival (%)
Autologous
bone
Bone
substitute
Combination
  • *

    95% confidence interval.

  • Quartile 25–Quartile 75.

  • NS, not specified.

Del Fabbro et al. (2008)59Lateral14484–9790–9693–95
Pjetursson et al. (2008)48Lateral7249–10076–10089–100
Tan et al. (2008)19Transalveolar60Not specifiedNot specifiedNot specified
Aghaloo & Moy (2007)42Lateral and transalveolar10287–97*67–100*83–93*
Chiapasco et al. (2006)62Lateral and transalveolar14461–10085–10075–100
Graziani et al. (2004)6Lateral and transalveolar72Not specifiedNot specifiedNot specified
Strietzel (2004)72Lateral and transalveolar6085–9489–9790–97
Wallace & Froum (2003)43Lateral and transalveolarNSNot specifiedNot specifiedNot specified
Tong et al. (1998)10Lateral6087–93*68–95*90–100*

A major concern with the use of AB is donor site morbidity (Nkenke et al. 2001, 2002, 2004). In the present review, three studies were included that also showed that donor site morbidity cannot be ignored (Watzek et al. 1998; Iturriaga & Ruiz 2004; Marchetti et al. 2007). It seems that donor site morbidity can be a major reason to question the use of AB.

On the other hand, allografts and xenografts used as alternatives to autografts have a potential for disease transmission (Cordioli et al. 2001). Infectious particles (prions) cause Creutzfeldt–Jakob disease (CJD) in humans and bovine spongiform encephalopathy (BSE) in cattle. Therefore, the use of xenogenic material for medical products and devices poses the question: to what degree such material can be considered free of prions and what are the risks of transmission of the disease to humans. Cases have been reported of iatrogenic transmission of CJD from humans to humans through the use of human-derived medicinal products (Brown et al. 1992). While the appearance of the new variant CJD (vCJD) appears to be caused through consumption of infectious bovine food, none of the vCJD patients had a history of surgery and the use of xenografts (Will et al. 1996). Allografts also pose the risk of transmission of other infectious diseases, such as acquired immunodeficiency syndrome. However, it has been stated that adequate material processing including freezing, demineralization, and lyophilization can decrease the risk of infection transmission to minimum (Gomes et al. 2008). Consequently, no case of transmission of one of the mentioned infectious diseases was described in the studies included in the present review. Although, none of the studies was designed to highlight the problem of disease transmission, it seems that the risk for transmission of these diseases by BS is minimal.

It is well known that sinus membrane perforation is a common technical problem that occurs in 19.5% (range 0–58.3%) of sinus floor elevations (Pjetursson et al. 2008). It has been stated that perforation of the sinus membrane does not compromise the osseointegration process or the survival of dental implants placed in an augmented maxillary sinus (Karabuda et al. 2006). A correlation between sinus membrane perforation and extended postoperative sinusitis or implant loss could not be found (Kaptein et al. 1998). The present review reveals that the advent of sinusitis, partial, or total graft loss is independent of the graft material. Using AB will not protect patients from developing sinusitis or graft loss.

Resorption of graft material and subsequent repneumatization have been mentioned as reasons to choose non-resorbable or slowly resorbable BS in sinus floor augmentation. However, the data of the present review do not reveal that resorption of the graft material has an influence on implant survival (Hallman & Nordin 2004; Kim et al. 2009). The aspect of resorption does not seem to be of concern that should prompt the clinician to prefer or abandon AB.

The height of the residual alveolar ridge was the basis for the decision of a staged approach or implant placement simultaneous with sinus floor augmentation in some studies. As the thresholds for one or the other procedure were chosen arbitrarily and had no scientific basis, the implant survival was comparable for the different graft materials used. The aspects of height of the residual alveolar crest and simultaneous or delayed implant placement did not seem to contribute to the decision of whether AB should be preferred in sinus floor augmentation or not. However, it has to be kept in mind that simultaneous implant placement is less invasive than a staged approach, more cost-effective, and more time-efficient (Becktor et al. 2008). However, this is true for every graft material used.

The healing periods elapsed after the different sinus floor augmentation procedures were also chosen arbitrarily in the different studies. Longer healing periods did not increase implant survival in a relevant way. Implant survival seemed not to be influenced by the healing periods of the different graft materials. The length of the healing period of the graft material could not be identified as a reason to prefer AB over BS.

The aspect of costs cannot be ignored in sinus floor augmentation procedures. Harvesting AB increases the operating time (Peleg et al. 2004). Especially, in case of extraoral donor sites, surgery is performed under general anesthesia (Watzek et al. 1998; Iturriaga & Ruiz 2004). In some studies the patients even had to be hospitalized (Marchetti et al. 2007). These different aspects lead to an increase in costs. It has to be assumed that the money spent on increased operating time, general anesthesia, and hospitalization will exceed the expenses for BS by far. Consequently, costs may not be a reason to prefer AB. However, detailed incremental cost-effectiveness analyses are needed to clarify this aspect.

From the present review, it is impossible to decide whether general diseases, smoking, or other risk factors have an influence on the implant survival rate depending on the graft material used.

Presently, it is not possible to decide whether the use of zytokines, growth factors, and BMPs will change the characteristics of AB or BS is way that one or the other material should be preferred as far as implant survival is concerned.

All in all, the current literature provides only a low level of evidence as far as the decision-making between the use of AB and BS is concerned. To date, studies are missing that are dedicated to the clarification of the influence of residual bone height, simultaneous or delayed implant placement, sinusitis, and graft resorption on implant survival in dependence of the graft material used. The aspects of donor site morbidity, disease transmission, and costs have also not been treated adequately.

Therefore, it seems that to date no clear aspects can be identified that should prompt the clinician to prefer AB over BS.

Conclusions

The available evidence neither supports nor refutes the superiority of AB over other graft materials for sinus augmentation with regard to implant survival or complications at the recipient site. Implant survival may be confounded by factors other than the graft material used for sinus floor augmentation.

Ancillary