## 5 Discussion  
Since certain vessels responsible for the blood supply of the posterior upper teeth may be found within the lateral bony sinus wall and underneath the Schneiderian membrane, opening the bone window and raising the Schneiderian membrane during the LSFE procedure may pose a risk to the vitality of adjacent teeth [8; 9; 18]. However, no loss of vitality or periapical pathology was found in any case in the present study. A strict surgical protocol and rigorous surgical technique make it possible to open the lateral window and to raise the Schneiderian membrane without damaging the tooth vascular bundle, thus preserving the blood supply. In most cases, lamina dura can be expected around the apex of the teeth with normal periapical tissues. In 4 out of the 18 patients, a single tooth was missing. In such cases, the surgical procedure is more difficult due to the restricted operating area and difficulty accessing the anterior sinus wall. Especially in these cases, caution should be practiced to prevent damaging the apex of adjacent vital teeth. In the current study, at least 3 mm of bone was preserved between the apex of the involved teeth and the lateral bone window margin, thus reducing the possibility of this complication. This is especially important in type 2-4 cases [11]. To the best of our knowledge, there have been no previous evaluations of tooth vitality following sinus floor augmentation involving thermal pulp vitality testing. The loss of tooth vitality has been reported following Le Fort 1 maxillary fracture without segmentalization. After Le Fort I osteotomy, electric and thermal pulp testing revealed that in 2/25 of the patients (8%), recovery took place after 10 days in the premolar and molar regions. Accordingly, following this procedure, the loss of tooth sensitivity can be expected in the short term; however, after 8 weeks, 24/26 of the patients showed full recovery, and at the end of the 24 weeks, all patients (100%) showed a full recovery of tooth sensitivity [18]. The results of the present study are in accordance with these results; however, it should be taken in consideration that LSFE is a more conservative and restricted procedure than Le Fort 1 maxillary fracture without segmentalization, especially taking into consideration that the caliber of the vessels supplying the lateral antral wall is rather large even in severe maxillary atrophy and after complete disappearance of the centro-medullary vessels [18]. Our report is in agreement with a previous publication by [PERSON] and colleagues [9]. [PERSON] reported a probability of \(\leq\)0.7% for tooth devitalization after maxillary sinus augmentation, which is an extremely rare complication. They found only a single case of tooth vitality loss out of 357 adjacent teeth, which might be attributable to the surgical procedure. Their conclusion was based only on retrospective analyses of periapical and panoramic radiographs. In their study, the authors claimed that the \"partial manipulation and/or disturbance of the blood supply most likely occurred during maxillary sinus augmentation, and this may explain the devitalization of tooth #26 and the need for endodontic therapy\" [9]. However, it appears from the X-ray that a loss of vitality could be due to several other reasons and not necessarily to the maxillary sinus augmentation. In the present study, all cases were evaluated clinically by vitality testing and radiographically by CBCT. The better diagnostic accuracy of CBCT for detecting periapical lesions has been well documented [15; 16], especially in combination with thermal pulp vitality testing 6 months after surgery. Our study involved only a limited number of cases; however, we used strict inclusion criteria and examined only LSFE cases with an extension of the surgical bone window laterally above the adjacent root apexes. The extension of the surgical window laterally allows the surgeon to gain better access for raising the Schneiderian membrane, thus limiting the incidence of membrane perforation as a complication.