This study was executed following the PRISMA criteria for the systematic review. An electronic search including MEDLINE (PubMed) and Cochrane database sites was conducted and supported by manual searching for targeted articles through the related journals and web sites from 1945 to 16 January 2017.

Prospective, retrospective studies and randomized clinical trials.

Articles published in English language only.

Human studies.

Healthy patients without systemic or local disease that may affect the maxillary sinus health or the sinus lift procedure outcome.

Studies which included at least six patients.

Sinus floor elevation via the transcrestal approach only (indirect sinus lift).

Follow-up period of at least 6 months.

Case reports and studies which included less than six patients.

Studies published in other language than English.

Experimental (animal studies).

Sinus floor elevation via lateral approach.

Maxillary sinus pathology or presence of sinus septa.

Studies with follow up period of less than 6 months.

The following keywords were involved in the electronic search:

MAILLARY SINUS AUMENATION, SINUS LIFT, INDIRECT SINUS LIFT, ANTRAL MEMEMBRANE ELEVATION, MINIMALLY INVASIVE ANTRAL BALLOON ELEVATION, ATROPHIC MAXILLA, SINUS FLOOR ELEVATION, SINUS MEMBRANE ELEVATION

The results (abstracts and articles) were reviewed twice by the same author at different time intervals. Hand searching for the full-text articles bibliographies of the selected studies was established. Sometimes the researchers were contacted to fill the missing information which was not mentioned in their articles or for more explanation about their results. The search process was demonstrated in (Fig. 1).