The objective of the present study is to present the current best evidence for enhancement of the vertical alveolar bone height and oral rehabilitation of the atrophic posterior maxilla with dental implants and propose some evidence-based treatment guidelines.
A comprehensive review of the English literature including MEDLINE (PubMed), Embase and Cochrane Library search was conducted assessing the final implant treatment outcome after oral rehabilitation of the atrophic posterior maxilla with dental implants. No year of publication restriction was applied. The clinical, radiological and histomorphometric outcome as well as complications are presented after maxillary sinus floor augmentation applying the lateral window technique with a graft material, maxillary sinus membrane elevation without a graft material and osteotome-mediated sinus floor elevation with or without the use of a graft material.
High implant survival rate and new bone formation was reported with the three treatment modalities. Perforation of the Schneiderian membrane was the most common complication, but the final implant treatment outcome was not influenced by a Schneiderian membrane perforation.
The different surgical techniques for enhancement of the vertical alveolar bone height in the posterior part of the maxilla revealed high implant survival with a low incidence of complications. However, the indication for the various surgical techniques is not strictly equivalent and the treatment choice should be based on a careful evaluation of the individual case. Moreover, further high evidence-based and well reported long-term studies are needed before one treatment modality might be considered superior to another.
Periodontal disease and dental caries are the main causes of tooth loss and the incidence of edentulous patients varies worldwide between 7% and 69% [
Different types of biomaterials have been used for maxillary sinus floor augmentation including autograft, allograft, xenograft, alloplast, and growth factors, and the selection of the ideal graft material has been a subject of controversy over the years. Autogenous bone graft is considered the golden standard in augmentation procedures due to its osteoinductive, osteogenic and osteoconductive characteristics [
Maxillary sinus floor augmentation using the lateral window technique was originally developed by Tatum [
Maxillary sinus floor augmentation applying the lateral window technique is usually performed under local anaesthesia and sedation. The maxillary sinus is exposed through the oral mucosa in the region of the anterior and lateral maxillary sinus wall. A midcrestal incision is made with posterior and anterior vertical releasing incisions. A mucoperiosteal flap with a trapezoid base is reflected exposing the lateral wall of the maxillary sinus. A trapdoor osteotomy is performed on the lateral wall of the maxillary sinus with burrs and a high-speed handpiece or piezoelectric surgery advoiding laceration of the Schneiderian membrane (
Maxillary sinus floor augmentation applying the lateral window technique with a grafting material.
A = A trapdoor osteotomy is performed on the lateral wall of the maxillary sinus.
B = The trapdoor is infractured and the Schneiderian membrane is carefully dissected and elevated from the maxillary sinus floor to create a compartment for placement of the graft material.
C = The implant is inserted simultaneously with the augmentation procedure.
D = The graft material is densely packed around the exposed implant surface in the created compartment.
Recent systematic reviews and meta-analysis have assessed the implant survival after maxillary sinus floor augmentation with various types of graft materials disclosing an overall implant survival rate well-beyond 90% [
Recent published systematic reviews assessing histomorphometric variables after maxillary sinus floor augmentation concluded that autogenous bone graft resulted in the highest amount of newly formed bone in comparison to various bone substitutes, though allografts, alloplastic materials and xenografts seemed to be a good alternative to autogenous bone graft [
Perforation of the Schneiderian membrane is the most common operative complication during maxillary sinus floor augmentation [
Maxillary sinus floor augmentation applying the lateral window technique with a grafting material is a safe and predictable surgical procedure with low morbidity for oral rehabilitation of the severely atrophic posterior maxilla with dental implants. This surgical intervention is recommended when the height of the residual alveolar bone is less than 6 mm. Dental implants are inserted simultaneously with the augmentation procedure, if the height of the residual alveolar bone provides sufficient primary implant stability. If not, then the implants are inserted 4 to 12 months after the augmentation procedure, depending of the used graft material.
Maxillary sinus membrane elevation using the lateral window technique without a graft material and simultaneous installation of implants was introduced by Lundgren et al. in 2004 [
The formation of the lateral window, elevation of the Schneiderian membrane and implant installation is similar to the surgical technique described above for maxillary sinus floor augmentation with a grafting material and simultaneous implant installation, although the implant bed is usually prepared with an undersized drilling protocol and the lateral cortical bony window is often dissected free and removed from the underlying Schneiderian membrane (
Maxillary sinus membrane elevation applying the lateral window technique without a graft material and simultaneous implant installation.
A = The lateral cortical bony window is dissected free and removed from the underlying Schneiderian membrane, which is carefully elevated from the maxillary sinus floor to create a compartment for placement of the graft material.
B = A blood coagulum is formed around the exposed implant tip in the secluded compartment between the elevated Schneiderian membrane and the original floor of the maxillary sinus.
C = The window to the maxillary sinus is covered by the dissected lateral cortical bony window.
D = New bone formation around the implant tip in the previous created compartment.
Recent systematic reviews and meta-analysis have assessed the implant survival after maxillary sinus membrane elevation using the lateral window technique without a graft material and simultaneous installation of implants disclosing an implant survival rate beyond 90% [
Assessment of intra-sinus new bone formation and bone density after maxillary sinus membrane elevation using the lateral window technique without a graft material has been compared with maxillary sinus floor augmentation applying the lateral window technique with autogenous bone graft or allogenic mineralized bone graft [
Perforation of the sinus membrane was the most frequent intraoperative complication, although very rare [
Maxillary sinus membrane elevation applying the lateral window technique without a graft material and simultaneous implant installation seems to be a safe and predictable surgical procedure with few complications and a high short-term implant survival rate. However, no consensus has yet been reached on the amount of bone formation and predictability for installation of numerous implants in the posterior part of the maxilla with this surgical intervention. Moreover, long-term clinical and radiographic studies assessing the final implant treatment outcome are scarce. Thus, further long-term comparative studies are needed before final conclusion can be provided about this surgical intervention for oral rehabilitation of the atrophic posterior maxilla with dental implants. It is our opinion that maxillary sinus membrane elevation using the lateral window technique without a graft material and simultaneous implant installation should solely be recommended for single implant installation, when a limited amount of bone regeneration is needed.
The osteotome-mediated transcrestal sinus lift approach was first proposed by Tatum in 1986 [
Osteotome-mediated sinus floor elevation and simultaneous installation of implants with or without the use of a graft material is performed under local anaesthesia and sedation. An intraoral midcrestal incision is made with or without a vertical releasing incision. Mucoperiosteum is reflected along the residual alveolar ridge and the implant position is marked on the alveolar crest with a small round bur. The implant bed is prepared with a series of osteotomes with increasing diameter or in combination with burrs to a depth approximately 1 to 2 mm away from the maxillary sinus floor boundary (
Osteotome-mediated sinus floor elevation and simultaneous installation of implants with or without the use of a graft material.
A = The implant bed is prepared with a series of osteotomes with increasing diameter or in combination with burrs to a depth approximately 1-2 mm away from the maxillary sinus floor boundary.
B = An up-fracture of the maxillary sinus floor is made with a mallet under light tapping and the Schneiderian membrane with the maxillary sinus floor is carefully elevated with the osteotome or a blunt instrument.
C = The implant is inserted in the residual alveolar bone with the implant tip exposed in the lifted area.
D = New bone formation around the implant tip in the previous created compartment.
Various systematic reviews and meta-analysis have assessed the implant survival after osteotome-mediated sinus floor elevation and simultaneous installation of implants with or without the use of a graft material revealing an overall implant survival rate higher than 90% [
The 3-year radiographic assessment of intra-sinus new bone formation after osteotome-mediated sinus floor elevation and simultaneous installation of implants ranged from 3.17 to 5.1 mm with a graft material and from 1.7 to 4.1 mm without a graft material, as documented in a systematic review and meta-analysis [
Perforation of the Schneiderian membrane is the most common operative complication after osteotome-mediated sinus floor elevation and simultaneous installation of implants with or without the use of a graft material with a mean incidence of 3.8% (range 0 to 21.4) [
Osteotome-mediated sinus membrane elevation is a predictable and reliable approach to oral rehabilitation of the atrophic posterior maxilla with a high implant survival rate. However, there is a paucity of long-term studies and installation of short implants (≤ 6 mm) significantly diminished the implant survival rate.
Hence, osteotome-mediated sinus membrane elevation is usually indicated when a residual vertical alveolar bone height of more than 6 mm is present. Autogenous bone graft or bone substitutes can be added, if more intra-sinus bone gain is needed for installation of implants with a desirable length.
Various surgical techniques have been proposed in order to achieve the necessary vertical alveolar bone height for the insertion of dental implants in the posterior part of the maxilla disclosing high implant survival rate with a low incidence of complications. However, the indication for the three above-mentioned surgical techniques is not strictly equivalent and the treatment choice should be based on a careful evaluation of the individual case. The residual vertical alveolar bone height and the ability to achieve primary implant stability is considered fundamental in deciding which augmentation technique should be used to obtain an adequate vertical bone height for installation of dental implants with a desirable length in the posterior part of the maxilla. When a residual vertical alveolar bone height of more than 5 mm is present, osteotome-mediated sinus floor elevation and simultaneous installation of implants with or without the use of a graft material is usually indicated. Otherwise, when the residual bone height is 5 mm or less, maxillary sinus floor augmentation using the lateral window technique with a grafting material lateral window approach is indicated (
Treatment guidelines for enhancement of the vertical alveolar bone height and oral rehabilitation of the atrophic posterior maxilla with implants.
Maxillary sinus membrane elevation using the lateral window technique without a graft material and simultaneous implant installation is solely suggested when a limited amount of bone regeneration is needed for installation of implants. However, further high evidence-based and well reported long-term studies are needed to clarify the specific indications for each treatment modality. Moreover, short dental implants or alternative treatment options should be considered for each individual patient.
The authors declare that there are no financial or other conflicts of interest related to this publication.