Maxillary sinus floor augmentation: a review of current evidence on anatomical factors and a decision tree

Abstract

Maxillary sinus floor augmentation using lateral window and crestal technique is considered as predictable methods to increase the residual bone height; however, this surgery is commonly complicated by Schneiderian membrane perforation, which is closely related to anatomical factors. This article aimed to assess anatomical factors on successful augmentation procedures. After review of the current evidence on sinus augmentation techniques, anatomical factors related to the stretching potential of Schneiderian membrane were assessed and a decision tree for the rational choice of surgical approaches was proposed. Schneiderian membrane perforation might occur when local tension exceeds its stretching potential, which is closely related to anatomical variations of the maxillary sinus. Choice of a surgical approach and clinical outcomes are influenced by the stretching potential of Schneiderian membrane. In addition to the residual bone height, clinicians should also consider the stretching potential affected by the membrane health condition, the contours of the maxillary sinus, and the presence of antral septa when evaluating the choice of surgical approaches and clinical outcomes.

Fig. 1

Three walls of confined space over the maxillary floor: the lateral wall of the maxillary sinus, the alveolar ridge crest, and the stretched and lifted maxillary sinus membrane

Fig. 2

Anatomical illustrations of maxillary sinus: a Type A-Stretch-favorable type (SFT); b Type B-Stretching-unfavorable type (SUT)

Fig. 3

Decision tree and CBCT classification: a A decision tree for choice of surgical approaches; b Relevant 3D CBCT Classification

Fig. 4

Case 1: a Pre-operative CBCT assessment, b surgical procedure, and c post-operative CBCT assessment of patient in case 1

Fig. 5

Case 2: a Pre-operative CBCT assessment, b surgical procedure, and c post-operative CBCT assessment of patient in case 2