No abstract

Background The aim of this comparative study was to evaluate the clinical outcome of nonrepair of the perforated maxillary sinus membrane compared to the nonperforated cases. Materials and Methods A retrospective comparative study was performed by identifying all lateral window sinus augmentation procedures, which were done during a defined period. Demographic data, systemic diseases, and smoking habits of patients were recorded. Thickness of the Schneiderian membrane and the amount of residual bone before surgery were measured by cone‐beam computed tomography (CBCT). In case of perforation, no attempt was made to repair the membrane. Alloplast was used for bone augmentation. The thickness of the Schneiderian membrane and gained bone height were recorded using CBCT at the time of prosthesis delivery. Results Sixty‐three patients with 65 sinuses were included in this retrospective study. The rate of sinus perforation was 39%. There was a significant association between the presence of sinus pathoses before surgery and the occurrence of Schneiderian membrane perforation (P = 0.03). The Schneiderian membrane was significantly thicker in patients with perforation compared to the patients without perforation (P < 0.001). There was no correlation between the size of the perforation and the thickness of the Schneiderian membrane. Most of the perforations (83%) occurred at the mesial and middle part of the lateral window. The Schneiderian membrane thickness was decreased significantly in both groups after the sinus elevation procedure (P < 0.05). The bone graft height was stable over the follow‐up period in both groups (P > 0.05). There was no implant failure in any of the groups. Conclusions Nonrepair of the Schneiderian membrane perforation did not adversely affect the clinical and radiographical outcomes. There were higher intraoperative and postoperative complications in the nonrepair group.

Objectives:To evaluate the long-term influence of residual bone height (RBH), sinus membrane perforation and the presence of voids on the survival of implants placed simultaneously with lateral maxillary sinus floor augmentation (MSFA). Materials and Methods:A total of 207 patients (613 implants) who underwent MSFA from 1999 to 2003 and followed up until 2018 were included in this study. RBH and marginal bone loss were assessed using a series of panoramic and periapical radiographs. Cumulative survival rates (CSR) with log-rank tests and hazard ratios of implant failure according to RBH, membrane perforation, and the presence of voids were assessed. Results:The overall 10-year and 20-year CSRs were 95% (95% CI: 84.95%-85.05%) and 85% (95% CI: 84.95%-85.05%), respectively. CSR was significantly higher for implants with ≥3 mm RBH (n = 260, 92.4%) than those with <3 mm RBH (n = 353, 78.8%) (p = .002). CSR of non-smoking group (n = 312, 90.0%) was higher than that of smoking group (n = 301, 77.1%) (p = .009). There was no significant difference in the hazard ratio of implant failure between the perforated membrane group (n = 245) and the non-perforated group (n = 368). In two out of 11 patients with voids, the inflammation of peri-implantitis progressed into voids, resulting in severe bone resorption. Conclusions:The survival of implants placed in <3 mm of RBH, even though it showed a lower CSR, could be considered acceptable. Neither sinus membrane perforation nor the presence of voids appeared to affect implant survival as long as supportive maintenance therapy with proper oral hygiene was provided. K E Y W O R D Sbone regeneration, bone substitutes, guided tissue regeneration, sinus floor elevation, smoking

Abstract:Ground water from springs and public supply wells was investigated for hydrochemistry and environmental isotopes of 3 H, 18 O and D in Jeju volcanic island, Korea. The wells are completed in a basaltic aquifer and the upper part of hydrovolcanic sedimentary formation. Nitrate contamination is conspicuous in the coastal area where most of the samples have nitrate concentrations well above 1 mg NO 3 -N/l. Agricultural land use seems to have a strong influence on the distribution of nitrate in ground water. Comparison of stable isotopic compositions of precipitation and ground water show that ground water mostly originates from rainy season precipitation without significant secondary modification and that local recharge is dominant.3 H concentration of ground water ranged from nearly zero to 5 TU and is poorly correlated with vertical location of well screens. The occurrence of the 3 H-free, old ground water is due to the presence of low permeability layers near the boundary of the basaltic aquifer and the hydrovolcanic sedimentary formation, which significantly limits ground water flow from the upper basaltic aquifer. The old ground water exhibited background-level nitrate concentrations despite high nitrate loadings, whereas young ground water had considerably higher nitrate concentrations. This correlation of 3 H and nitrate concentration may be ascribed to the history of fertilizer use that has increased dramatically since the early 1960s in the island. This suggests that 3 H can be used as a qualitative indicator for aquifer vulnerability to nitrate contamination.