Low Window Sinus Elevation Technique: Bone Gain and Postsurgical Discomfort. A Retrospective Case Series.

Recently, the Low Window technique was proposed to facilitate sinus augmentation and reduce postsurgical patient discomfort. It was shown to be both safe and effective. This case series evaluates the postsurgical discomfort of patients undergoing Low Window sinus augmentation, the bone gain achieved, and whether these factors correlate with the osteotomy area. Records of patients (n = 26) who underwent a sinus elevation using the Low Window approach (n = 34 interventions), followed by implant placement and prosthetic rehabilitation (n = 97 implants), were assessed retrospectively. The analyzed outcomes were the medial, middle, and lateral bone gain ≥ 9 months after augmentation; pain at 5 to 6 hours postsurgery, evaluated on a visual analog scale (VAS; 0 to 100); pain, swelling, and hematoma formation every day up to 7 days postsurgery, evaluated by VAS; implant and prosthetic success and survival rates; and rate of complications. The average follow-up time was 62.1 ± 14.9 months. No intraoperative sinus membrane perforations or other complications occurred. Medial, middle, and lateral bone gains were 10.1 ± 1.7 mm, 11.6 ± 0.8 mm, and 10.7 ± 0.9 mm, respectively. At the last follow-up, the implant success rate was 99%. Postsurgical VAS pain 5 to 6 hours postsurgery was 12.3 ± 8.0 and decreased significantly thereafter. Swelling prevalence was 29.4% at 1 day postsurgery, 20.6% at 2 days, and 2.9% the following day. No swelling was observed from day 4 onward. Prevalence of hematoma was 8.8% for 2 days postsurgery, 2.9% the day after, and no hematoma was observed thereafter. Only the osteotomy area correlated with immediate postsurgical pain, but not with other discomfort outcomes or with bone gain. Low Window sinus elevation might allow bone gain and medium-term implant and prosthetic success rates similar to that of other access window designs. Prospective, comparative studies are needed to investigate whether the technique is more advantageous than traditional approaches.

The Low Window Technique: Comparison between Manual and CAD/CAM-guided Design.

AIM: The aim of this bench study was to provide quantitative data addressing the difference between the manual low window design and the corresponding computer-aided design and computer-aided manufacturing (CAD/CAM)-guided design. MATERIALS AND METHODS: Five cone-beam computed tomography (CBCT) scans of as many patients (two males and three females, age range: 61-78 years) with partially edentulous maxilla to be rehabilitated through sinus augmentation, one- or two-step implant placement, and implant-supported prostheses were used to 3D-print the corresponding five maxillary stereolithographic models. Five independent highly skilled maxillofacial surgeons, who were provided with the patients' orthopantomographs, drew on the models the access windows for sinus augmentation according to the "high" (standard) and the low window design both by free-hand and using a surgical guide prepared by computer-guided design. Accuracy and inter-operator variability were analyzed. RESULTS: The results of this study showed that the manual design is associated with a clinically relevant shift in the low window shape, size, and positioning compared with the CAD/CAM-based positioning. All four directions (apical, coronal, mesial, and distal) showed on average the same extent of placement error (approximately 3 mm). Overall, the intra-operator variability was very similar, and measurements were not influenced by the operator (low inter-operator variability). CONCLUSION: The compromised accuracy and reproducibility in the manual design may limit the advantages of the low window technique. Thus, within the limits of this study, the computer-guided approach should be preferred vs the manual approach when performing a low window sinus lift. This may limit intra- and postoperative complications, as well as patient discomfort. CLINICAL SIGNIFICANCE: The "best option" CAD/CAM-guided design should be chosen when performing a low window sinus lift because it reduces discrepancies in selected parameters both between and within groups. This should facilitate the achievement of better results by dentists who have insufficient experience performing implant surgery.

The Low Window Sinus Lift: A CAD-CAM-Guided Surgical Technique for Lateral Sinus Augmentation: A Retrospective Case Series.

INTRODUCTION: Recently, a rational design of the window osteotomy, the "Low Window" technique, was proposed to facilitate sinus augmentation and reduce postsurgical patient discomfort; this article aims to evaluate its safety and effectiveness. MATERIALS AND METHODS: Records were assessed retrospectively for patients who had sinus lifts using the low window approach, followed by implant placement and prosthetic rehabilitation. Outcomes analyzed were implant and prosthetic success and survival rates and rate of complications. Patients also provided their subjective evaluation on postoperative pain and swelling. DISCUSSION: Records of 22 patients who had 28 interventions (79 implants) were assessed. Average follow-up was 38.4 ± 13.2 months. No cases of intraoperative sinus membrane perforation or other complications occurred, and patients reported a high degree of satisfaction. At the final follow-up, all prostheses and implants were successful. CONCLUSION: The low window sinus lift seems to be an effective technique for reducing the risk of sinus-membrane perforation and patient postsurgical discomfort in lateral sinus augmentation. Prospective, comparative studies are needed to investigate whether the technique is more advantageous than the traditional lateral osteotomy and flap-preparation approaches.