Changes in the Maxillary Sinus Membrane Thickness and Sinus Health Following Lateral Sinus Floor Elevation: Comparing Preoperative Mucosal Thicknesses of Less than and Greater than 5 Millimeters.

PURPOSE: To investigate the effect of lateral sinus floor elevation (LSFE) on sinus membrane (SM) thickness and sinus health in mucosa thickness less and more than 5 mm. MATERIALS AND METHODS: LSFE was performed in a prospective controlled clinical trial on two groups with less than and more than 5 mm (group A & B) SM thickness and followed for 6 months. Using preoperative and 6-month postoperative CBCT and clinical evaluation, SM thickness changes (primary outcome variable), sinus health, augmented bone height, and length (augmentation adequacy), membrane-related variables, and operation time were measured. RESULTS: Forty unilateral sinus augmentations (A:20, B:20) with simultaneous installation of 52 fixtures were performed on 40 subjects (72.5% males, mean age of 48.8±7.6). The mean preoperative and 6- month SM thicknesses in group A and group B were 1.4±0.9 and 1.3±0.6 mm, and 6.8±1.0 and 3.4±1.7 mm, respectively. The mean postoperative SM thickness significantly decreased (P<0.001) only in group B. The mean SM thickness changes also revealed a noticeable difference between the two groups (P<0.001). Augmentation adequacy and membrane perforation rate were similar in both groups. Clinical and radiographic rhinosinusitis was not detected in any of the patients. Bleeding during separation and resistance to elevation in group B were significantly higher than in group A (P=0.003, P=0.001). Surgical time in group B (12.08 ± 8.26 minutes) was longer than in group A (8.64 ± 3.70 minutes), without reaching a significant level (P=0.097). CONCLUSIONS: LSFE in thickened mucosa (≤10 mm) and thinner mucosa (≤5 mm) does not cause abnormal changes in the sinus membrane and sinus health. LSFE in thickened mucosa results in adequate sinus augmentation. Thickened SM also shows a significant thickness reduction. The thickened membrane does not appear to be a contraindication to SFE.

Impact of 2 Lateral Nasal Osteotomy Techniques on the Periorbital Subunits.

PURPOSE: The periorbital area undergoes a series of postoperative sequelae after rhinoplasty. PATIENTS AND METHODS: Between January 2015 and January 2016, 50 patients aged between 19 and 46 years who underwent rhinoplasty qualified for the study. Of these patients, 25 were chosen for each group: One group underwent a low-to-low lateral nasal osteotomy, and the other group underwent a low-to-high lateral nasal osteotomy. Six specific periocular findings were designated and recorded to measure differences in the outcomes of the 2 osteotomy techniques. Specific periocular findings included the amount of scleral show as measured through the marginal reflex distance; lateral and medial scleral surface area; and palpebral fissure height, width, and inclination. RESULTS: There were no significant differences in any of the outcome variables at different intervals between the 2 groups (P > .05) except for palpebral fissure inclination after 3 months (P = .02). CONCLUSIONS: According to the results and considering the inherent limitations of the study, it can be concluded that both low-to-low and low-to-high techniques are similar and have no considerable permanent effects on the periorbital region.

Effect of conventional and contemporary disinfectant techniques on three peri-implantitis associated microbiotas.

PURPOSE: To evaluate the antiseptic properties of five different disinfectant techniques on three different peri-implantitis (PI) associated biofilms. METHODS: 90 implant titanium disks, with the same thickness and diameter, were prepared and randomly divided into 18 groups (n = 5) based on the microbiota strains (S. aureus, S. epidermidis and C. albicans) and using the following disinfectant techniques:soft laser therapy, photodynamic therapy (PDT), 0.12% NaOCl, 0.2% chlorhexidine, 3% H2O2, and control groups. After forming a protein layer on disk surfaces, the specimens were exposed to the microbial suspensions. After decontamination according to designated techniques, 2% Trypsin protease was administered to isolate the surviving microorganisms. Muller Hinton agar culture was used for microbiota growth. After 48-hour incubation, the standard colony forming unit (CFU) was assayed and the collected data were analyzed by Kruskal-Wallis and Mann-Whitney tests at a significance level of 0.05. RESULTS: The highest amount of CFU/ml values was shown by C. albicans, which was subjected to PDT (25.12 ± 30.23). The least disinfecting efficacy on S. epidermidis was demonstrated by the laser group (all P-values ≤ 0.01). Nevertheless, all of the groups exhibited significant differences with the control groups (all P-values < 0.01). CLINICAL SIGNIFICANCE: None of the studied disinfectant techniques had the highest lethal effects on all of the tested microbiotas. Therefore, a combination of these disinfectant techniques, for instance PDT ⁺ 3% H2O2 or 0.2% chlorhexidine, is recommended.

Flexural strengths of implant-supported zirconia based bridges in posterior regions.

PURPOSE: Impact forces in implant supported FDP (fixed dental prosthesis) are higher than that of tooth supported FDPs and the compositions used in frameworks also has a paramount role for biomechanical reasons. The aim of this study was to evaluate the flexural strength of two different zirconia frameworks. MATERIALS AND METHODS: Two implant abutments with 3.8 mm and 4.5 mm platform were used as premolar and molar. They were mounted vertically in an acrylic resin block. A model with steel retainers and removable abutments was fabricated by milling machine; and 10 FDP frameworks were fabricated for each Biodenta and Cercon systems. All samples were thermo-cycled for 2000 times in 5-55℃ temperature and embedded in 37℃ artificial saliva for one week. The flexural test was done by a rod with 2 mm ending diameter which was applied to the multi-electromechanical machine. The force was inserted until observing fracture. The collected data were analyzed with SPSS software ver.15, using Weibull modulus and independent t-test with the level of significance at α=.05. RESULTS: The mean load bearing capacity values were higher in Biodenta but with no significant differences (P>.05). The Biodenta frameworks showed higher load bearing capacity (F0=1700) than Cercon frameworks (F0=1520) but the reliability (m) was higher in Cercon (m=7.5). CONCLUSION: There was no significant difference between flexural strengths of both zirconia based framework systems; and both Biodenta and Cercon systems are capable to withstand biting force (even parafunctions) in posterior implant-supported bridges with no significant differences.

Evaluation of light curing distance and mylar strips color on surface hardness of two different dental composite resins.

INTRODUCTION: Hardness is one of the basic properties of dental materials, specially composite resins which is relevant to their polymerization. The aim of this study was to evaluate the effect of light curing distance and the color of clear Mylar strips on surface hardness of Silorane-based (SCR) and Methacrylate-based composite resins (MCR). MATERIALS AND METHODS: 40 samples of MCRs (Filtek Z250) and SCRs (Filtek P90) were prepared in size of 5 mm×2 mm (80 samples in total). The samples divided into 8 groups (10 samples in each one) based on the color of clear Mylar strips (white or blue) and distance from light curing source (0 mm or 2 mm). All the samples cured for 40 second and stored in incubator for 24 hours in 37°C temperature. Surface hardness test was done by Vickers test machine and the collected data were analyzed by one-way ANOVA and paired T-test by using SPSS software version 13 at significant level of 0.05. RESULTS: MCRs cured with blue Mylar strips from 0 mm distance had the highest (114.5 kg/mm(2)) and SCRs cured with white Mylar strips from 2 mm distance had the lowest (42.2 kg/mm(2)) mean of surface hardness. Also, the results of comparison among SCRs and MCRs showed significant differences among all groups (all P values <0.01). CONCLUSION: The hardness decreased as the distance increased and the blue Mylar strips provided higher hardness than clear ones. Also, Filtek Z250 showed higher hardness compared to Filtek P90.

The effect of eugenol-free temporary cement's remnants on retention of full metal crowns: comparative study.

INTRODUCTION: The aim of this study was to evaluate the effects of eugenol-free temporary cement's remnants on the retentive strength of full metal crowns luted via zinc phosphate and resin cement (Maxcem) to the tooth structure. MATERIALS AND METHODS: Forty complete standardized Ni-Cr crowns in four groups were cemented by two types of permanent cements: zinc phosphate cement and resin cement (Maxcem). In the two groups before permanent cementation of crowns, temporary acrylic crowns were cemented by eugenol-free temporary cement. Crowns' retention was evaluated by Universal testing machine. All data were analyzed by means of one-way ANOVA test in SPSS software version 11.5 (α=0.05). RESULTS: There was no significant difference in groups with prior using eugenol-free temporary cement and groups with just using two permanents cement (p-value≥0.05). DISCUSSION: The application of temporary cement before permanent cementation of full metal crowns does not have any adverse effect on retention of full metal crowns, when temporary cements are removed properly.