Temperature-independent pitch invariance in cholesteric liquid crystal.

We report a pitch invariance in cholesteric liquid crystals (CLCs) independent of temperature by mixing two chiral dopants. One dopant tends to shorten the helical pitch of the CLC, but the other makes the pitch longer, with increasing temperatures. From an analysis of temperature dependencies of the pitch for each dopant, we determined the mixing ratio of two chiral dopants for the pitch invariance. Finally, we obtained the pitch-invariant CLCs to temperature and the helical twisting power of the mixed dopant was estimated.

Benefit of the replaceable bony window in lateral maxillary sinus augmentation: clinical and histologic study.

PURPOSE: This retrospective study demonstrates, by clinical and histologic evaluation, the benefit of the replaceable bony window as a homologous bony barrier in lateral sinus augmentation. MATERIALS AND METHODS: A total of 103 maxillary sinus augmentations were performed using a piezoelectric device and a Er,Cr:YSGG laser apparatus. The detached bony windows were repositioned over various bone grafts. Sixteen bone biopsy specimens were harvested at the time of uncovering or implant placement. RESULTS: Three sinuses developed postoperative infections (2.91%). After 6 to 8 months of healing, uncovering procedures were carried out. Radiographically, reconstruction of the lateral sinus wall was observed in all cone-beam computed tomogram. Clinically, complete bone healing between the replaceable bony window and the lateral sinus wall was observed in all cases, except for the 3 infected sinuses (100 sinuses, 97.09%). Histologically, favorable new bone formation was observed in all specimens without any fibrous connective tissue invagination. More mature bone was observed along the floor of the replaceable bony window than at the center of the graft site. CONCLUSION: This study demonstrates that the replaceable bony window acts as an osteoinductive homologous barrier membrane over various bone graft materials and accelerates new bone formation in lateral sinus augmentation.

Polarizer-free liquid crystal display with electrically switchable microlens array.

We propose a polarizer-free liquid crystal display (LCD) with an electrically switchable microlens array. The incident lights are controlled to focused or defocused states by index matching of the lens polymer and LC layer. By adopting two light-blocking masks that have a circular stop pattern and the complementary open pattern, the LCD was able to realize the entire gray scale. Additionally, to achieve fast response time characteristics, we introduce polymerized RMs within the alignment layers.

Minimally invasive sinus augmentation using ultrasonic piezoelectric vibration and hydraulic pressure: a multicenter retrospective study.

PURPOSE: The purpose of this study was to evaluate the success rate of implants and vertical bone gain of edentulous posterior maxilla using ultrasonic piezoelectric vibration and hydraulic pressure, namely the hydrodynamic piezoelectric internal sinus elevation (HPISE) technique through a crestal approach. MATERIALS AND METHODS: A total of 250 maxillary sinuses were augmented using HPISE and 353 implants (averaging 11.8 mm in length and 4.5 mm in diameter), with 12 different systems, were placed simultaneously with or without additional bone grafting. Plain radiograms and cone beam computed tomograms were taken in all patients to evaluate sinus augmentation. RESULTS: Membrane perforation was recorded at 10 of the 353 implant sites. The perforation rate was 2.83%. The total success rate of implantation was 97.2% after an average of 69.3 weeks of loading. CONCLUSION: The crestally approached sinus augmentation using ultrasonic piezoelectric vibration and hydraulic pressure is an additional method of maxillary sinus augmentation.

Bone regeneration in the maxillary sinus using an autologous fibrin-rich block with concentrated growth factors alone.

PURPOSE: The purpose of this study was to evaluate the predictability of new bone formation in the maxillary sinus using an autologous fibrin-rich blocks with concentrated growth factors (CGFs) alone as an alternative to graft material. MATERIALS AND METHODS: A total of sixty-one sinus grafts were consecutively performed using the lateral window approach. After making replaceable bony window, the sinus membrane was elevated to make a new compartment. After 113 implants (average 13 mm high) with 11 different systems were placed simultaneously, the collected fibrin-rich blocks with CGFs alone were inserted in the sinus. To seal the lateral window, the bony window was repositioned. Radiographic, clinical, and histologic evaluation was performed to verify sinus augmentation. RESULTS: No significant postoperative complications developed. New bone consolidation in all augmented maxillary sinus was observed along the implants on plain radiographs and on cone-beam computed tomograms. The success rate of implant was 98.2% after an average of 10 months loading. CONCLUSION: Fibrin-rich blocks with CGFs act as an alternative to bone grafting and can be a predictable procedure for sinus augmentation.

New bone formation in the maxillary sinus using peripheral venous blood alone.

PURPOSE: The purpose of this study was to evaluate the amount of bone formation under a sinus membrane tented with implants and filled with venous blood as a graft material. MATERIALS AND METHODS: Fourteen patients (17 sinus augmentations) were consecutively treated with sinus floor elevation via the lateral window approach. The lateral bony window was created using a piezoelectric saw, and the sinus membrane was elevated to make a new compartment. After resorbable blast media-surfaced dental implants were placed simultaneously, the collected peripheral venous blood was applied to support the sinus membrane over the implant apex, and the bony portion of the lateral window was repositioned to seal the lateral window. In 6 cases, samples were taken for biopsy at the time of second stage surgery. RESULTS: An average of 6.8 months after the sinus augmentation, new bone consolidation in the maxillary sinus was observed by radiographic and histologic evaluation. Vital bone formation was 38.70% according to the histomorphometric data. Of the 31 implants placed, 2 failed. The overall implant survival rate was 93.5%. All failures occurred when implants were placed into the extraction socket and were associated with poor initial stability. CONCLUSION: This study suggests that simultaneous placement of dental implants and injection of peripheral venous blood as a graft material appears to be a safe alternative procedure for maxillary sinus augmentation.

Retrospective multicenter analysis of immediate provisionalization using one-piece narrow-diameter (3.0-mm) implants.

PURPOSE: The aim of this retrospective analysis was to report on the clinical outcome of immediate provisionalization using one-piece narrow-diameter implants. MATERIALS AND METHODS: The dental records of patients who received narrow implants were reviewed. Narrow-diameter (3.0-mm) one-piece implants were used to support restorations of missing maxillary lateral incisors and mandibular incisors. All implants were placed in a one-stage procedure according to the protocol recommended by the manufacturer, with immediate placement of provisional restorations. Following an average healing period of 3 months in the mandible and 5 months in the maxilla, the definitive prostheses were fabricated. The survival rate of the implants was analyzed, and radiographic evaluation was performed. RESULTS. Thirty-six patients (20 men and 16 women), aged from 42 to 72 years (average age of 53 years), were treated with 62 one-piece narrow implants. A success rate of 100% was observed over a period up to 33 months (mean, 23 ± 4.3 months). Among these, 8 implants were placed in maxillary lateral incisor positions and 54 implants were placed in mandibular incisor areas. Forty-four implants supported fixed partial prostheses, and 18 implants supported single crowns. The majority of the implants were 15 mm in length. Mean marginal bone loss at the 12-month follow-up visit was 0.53 ± 0.37 mm (range, 0 to 1.4 mm). CONCLUSIONS: The results obtained in this retrospective analysis suggest that the one-piece narrow-diameter implant can predictably restore missing maxillary lateral incisors and mandibular incisor with narrow interdental spaces and labiolingual widths.