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: firstname.lastname@example.org
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
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.
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.
The inclusion criteria for study selection were:
(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.
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).
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
Bovine spongiform encephalopathy
Deproteinized bovine bone mineral
Demineralized freeze-dried bone allograft
Irradiated cancellous bone
Macroporous biphasic calcium phosphate
Prospective comparative case series
Prospective case series
Platelet rich plasma
Retrospective comparative case series
Retrospective case series
New variant Creutzfeldt–Jakob disease
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
Design of study
Number of patients (n)
Age range (years)
Mean age (years)
Residual bone height (mm)
NS, not specified; PCCS, prospective comparative case series; PCS, prospective case series; RCCS, retrospective comparative case series; RCS, retrospective case series.
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).
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.
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).
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).
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
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.
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.