A line is drawn from the nasal tip to the most anterior point of the lower lip. The distance from soft tissue pogonion to the ideal soft tissue pogonion is the amount of correction. Alloplastic augmentation does not correct the soft tissue in a 1:1 ratio. In the case of a patient having normal soft tissue(8~11 mm), the ratio of the soft tissue correction is 1:0.66. In the case of a patient having a soft tissue deficiency(less than 7mm), the ratio of the soft tissue correction is 1:0.8. In the case of a patient having a soft tissue excess(more than 12mm), the ratio of the soft tissue correction is 1:0.5. The length of the implant is required to be more lateral to the mental foramen by 1~1.5 cm for restoration of the prejowl sulcus. The posterior surface of the implant must be carved to shape precisely to the bony surface. I usually make several vertical etchings and 20~30 holes in the implant. The vertical etchings help expand the implant to securely fit the mandibular contour. Fenestrated silastic implants can be further stabilized with fibrous tissue ingrowth and future reconstruction if bony erosion occurs.
Chin ; Dimethylpolysiloxanes ; Humans ; Lip ; Silicone Elastomers

PURPOSE: To investigate postoperative outcomes of endonasal dacryocystorhinostomy (DCR) using lacrimal sac flap and silastic sheet in patients with acquired nasolacrimal duct obstruction. METHODS: From November 2009 until December 2010, endonasal DCR with lacrimal sac flap was performed in 26 eyes (group 1) and conventional DCR without flap in 28 eyes (group 2). The anatomic and functional success rates and complications were analyzed and compared between the 2 groups. RESULTS: The anatomical success rate was 96.2% in group 1 and 85.7% in group 2. The functional success rate was 100% in group 1 and 92.9% in group 2. The success rate was higher in group 1 than in group 2, although not being statistically significant. Granuloma was found in 15.4% of patients in group 1 and 32.1% of patients in group 2. Synechia or membranous obstruction was not found in group 1, whereas synechia developed in 14.3% of patients in group 2. CONCLUSIONS: Endonasal DCR with lacrimal sac flap showed a greater success rate and lower formation of granuloma than conventional endonasal DCR without flap because of reduced inflammation and granulation tissue formation around retained bony spicles.
Dacryocystorhinostomy ; Dimethylpolysiloxanes ; Eye ; Granulation Tissue ; Granuloma ; Humans ; Inflammation ; Nasolacrimal Duct

The most possible complication of transnasal reconstruction of medial orbital wall fracture is infection of the dependent sinuses. As a result, endoscopic reduction in a medial blowout fracture with sinusitis and nasal polyp has been avoided. The silastic sheet and Merocel packing, which are placed in the ethmoid sinus, may cause or worsen sinusitis since they could cover up the natural ostia in the vicinity of sinuses. The spread of infection into the orbital wall and the difficulty of recognizing between herniated orbital tissues, infection and nasal polyp makes it difficult to perform endoscopic reduction when there are concomitant sinusitis and nasal polyp. The author reports three recently encountered cases of endoscopic reduction of medial blowout fracture with sinusitis and nasal polyp.
Dimethylpolysiloxanes ; Ethmoid Sinus ; Formaldehyde ; Nasal Polyps ; Orbit ; Polyvinyl Alcohol ; Sinusitis

The rapid screening of tumor markers is a challenging task for early diagnosis of cancer. This study aims to use highly sensitive chemiluminescent protein microarray technology to efficiently screen a variety of low abundance tumor related markers. A new material, termed integrated polydimethylsiloxane modified silica gel (iPDMS), was obtained by adding a surface polymerization initiator with olefin end to the conventional polydimethylsiloxane, and fixing into the three-dimensional structure of polydimethylsiloxane by thermal crosslinking through silicon hydrogen bonding. In order to make the iPDMS material resistant to non-specific protein adsorption, a poly(OEGMA) polymer brush was synthesized by surface-initiated atom transfer radical polymerization at the active initiation site. Finally, 20 tumor-related antigens were printed into the specific areas of the microarray by high-throughput spray printing technology, and assembled into 48-well detection microtiterplates of the iPDMS microarray. It was found the VEGFR and VEGF121 autoantibodies that obtained from 8 common tumors (breast cancer, lung cancer, colon cancer, gastric cancer, liver cancer, leukemia, lymphoma and ovarian cancer) can be used as potential tumor markers. The chemiluminescence labeled iPDMS protein microarray can be used for the screening of tumor autoantibodies at early stage.
Adsorption ; Autoantibodies ; Dimethylpolysiloxanes ; Protein Array Analysis ; Silica Gel ; Surface Properties

Polydimethylsiloxane (PDMS) and hydroxyapatite (HA) were combined in our laboratory to fabricate an elastic porous cell scaffold with pore-forming agent, and then the scaffold was used as culture media for rat bone marrow derived mesenchymal stem cells (rBMSCs). Different porous materials (square and circular in shape) were prepared by different pore-forming agents (NaCl or paraffin spheres) with adjustable porosity (62%-76%). The HA crystals grew on the wall of hole when the material was exposed to SBF solutions, showing its biocompatibility and ability to support the cells to attach on the materials.
Animals ; Biocompatible Materials ; chemistry ; Dimethylpolysiloxanes ; chemistry ; Durapatite ; chemistry ; Mesenchymal Stromal Cells ; cytology ; Porosity ; Rats ; Tissue Scaffolds

OBJECTIVEThe biological safety of a new developed silicone rubber for inflatable silastic prosthesis (SRISP) was evaluated.

METHODSFollowing the GB/T 16886.10-2005 standard, YY/T 0127.13-2009 standard, and GB/T 16886.11- 2011 standard, samples were prepared and tested by animal experiments, such as guinea pig maximization test, oral mucous membrane irritation test, and short-term systemic toxicity test (oral route).

RESULTSNo obvious erythema and edema in the guinea pig abdominal skin were observed after 24, 48, and 72 h of stimulating touch, thus indicating that SRISP does not cause potential skin sensitivity. No local response to SRISP was found, and the visual observation and pathological findings of oral mucosa were normal and similar to that of the control group. Therefore, SRISP had no irritation response to oral mucosa. No clinical signs of toxicity were observed in rats, and no significant differences in weight and weight relative growth rate between extract group and blank control group (P > 0.05) were found. Thus, SRISP had no short-term systemic toxicity.

CONCLUSIONThese results indicated that SRISP met the requirement of biomedical materials and had good bio- security.

OBJECTIVETo compare shear bond strength (SBS) between two types of silicone soft liner and polymethyl methacrylate (PMMA) under the condition of heat curing and room temperature curing.

METHODSA total of 48 PMMA specimens (50 mm x 10 mm x 3 mm) were made by water-bath heating method, and randomly divided into four groups. By using Ufi Gel P (UGP) as soft liner material, group A1 was prepared under heat curing, and group A2 was prepared under room temperature curing. To form the other two groups, Silagum-Comfort (SLC) as soft-liner material was used. Group B1 was prepared under heat curing, and group B2 was prepared under room temperature curing. Shear bond strength (SBS) was tested by using the electronic universal testing machine. The adhesives layer and surface of silastic and PMMA were observed by optical microscope and scanning electron microscopy (SEM).

RESULTSThe SBS of groups A1, A2, B1, B2 were (2.39 +/- 0.24), (1.74 +/- 0.27), (3.09 +/- 0.26), and (2.21 +/- 0.29) MPa, respectively. Significant differences were found between A1 and A2, B1 and B2, A1 and B1, and A2 and B2 (P < 0.05). Optical microscope showed numerous bubbles in the cured UGP, and no air bubbles in the SLC. The surface of PMMA was rough. SEM images showed that each group had continual consistent adhesive interface and a whisker hump on the adhesive layer of A2 and B2.

CONCLUSIONThe SBS ofUGP, SLC, and PMMA achieved minimum clinical standard of 0.44 MPa. The SBS of UGP and PMMA were higher than that of SLC and PMMA. The polymerization method of heat curing was higher than room temperature curing.

PURPOSE: To compare the clinical outcome of silicone tube intubation according to the tie methods. METHODS: Eighty-eight eyes of 87 patients who underwent silicone tube intubation were divided into two groups based on the tie method: a silicone silastic sheet group (Group 1, n=59) and a nylon 6-0 suture knot group (Group 2, n=29). The two groups were compared according to their success rates, recurrence rates and complications. RESULTS: No significant difference was found in the success rate between the two groups (83.0% in Group 1 and 82.7% in Group 2). However, Group 2 showed a significantly higher rate of postoperative complications than Group 1. In Group 1, 5/59 (8.4%) eyes had ocular irritation, 2/59 (3.4%) eyes exhibited tube prolapse, conjunctivitis, corneal erosion, and dacryocystitis and 1/69 (1.6%) eyes had a punctal slit after intubation. In Group 2, 3/29 (10.3%) eyes had ocular irritation, 2/29 (6.9%) eyes exhibited tube prolapse, conjunctivitis, a punctal slit, and dacryocystitis, and 1/29 (3.4%) eyes showed corneal erosion, or a granuloma after intubation. A recurrence of symptomatic tearing was found in 6/59 (10%) eyes in Group 1 and 3/29 (10%) in Group 2. CONCLUSIONS: In silicone tube intubation of incomplete NLD obstruction, the usage of silicone silastic sheets to tie both ends of the silicone tube produced a lower complication rate and a higher success rate than that of the suture knot group. Lower tension on the nasolacrimal passage in the silicone silastic sheet group allows for a significantly lower rate of punctal slit development. Therefore, the method of using silicone silasitic sheets can be considered useful in the treatment of NLD obstruction.
Conjunctivitis ; Dacryocystitis ; Dimethylpolysiloxanes ; Eye ; Granuloma ; Humans ; Intubation ; Nasolacrimal Duct ; Nylons ; Postoperative Complications ; Prolapse ; Recurrence ; Silicones ; Sutures

OBJECTIVE: This study was performed to evaluate the frequency of nasal septal perforation at the suture fixation site of a silastic sheet inserted during nasal surgery. METHODS: Seven hundred and twenty-one patients with silastic sheet insertion during common nasal surgeries were examined. The frequency of perforations and subjective symptoms of the patients were evaluated. RESULTS: Nasal septal perforation at the suture fixation site occurred in seven patients (0.97%). In three patients, perforations occurred immediately after removal of the sheet, while four patients developed perforations 2 to 4 weeks later. In most cases, perforations were small and did not exceed 2 to 3 mm in diameter. No patient complained of nasal symptoms related to the septal perforation postoperatively. CONCLUSION: The frequency of the septal perforation at the suture fixation site of a silastic sheet was very low and subjective symptoms were absent.
Dimethylpolysiloxanes ; Humans ; Nasal Septal Perforation ; Nasal Septum ; Nasal Surgical Procedures ; Sutures

PURPOSE: Purpose of this study was to evaluate effect of two surface treatments, sandblasting and monomer treatment, on tensile bond strength between two long term resilient liners and poly (methyl methacrylate) denture base resin. MATERIALS AND METHODS: Two resilient liners Super-Soft and Molloplast-B were selected.Sixty acrylic resin (Trevalon) specimens with cross sectional area of 10x10 mm were prepared and divided into two groups of 30 specimens each. Each group was surface treated (n = 10) by sandblasting (250 micro alumina particles), monomer treatment (for 180 sec) and control (no surface treatment). Resilient liners were processed between 2 poly(methyl methacrylate) surfaces, in the dimensions of 10x10x3 mm. Tensile strength was determined with Instron Universal testing machine, at a crosshead speed of 5 mm/min; and the modes of failure (adhesive, cohesive or mixed) were recorded. The data were analyzed using one-way ANOVA, followed by Tukey HSD test (alpha = 0.05). RESULTS: Monomer pretreatment of acrylic resin produced significantly higher bond strengths when compared to sandblasting and control for both resilient liners (P < .001). Sandblasting significantly decreased the bond strength for both the liners when compared to monomer pretreatment and control (P < .001). Mean bond strength of Super-Soft lined specimens was significantly higher than Molloplast-B in various surface treatment groups (P < .05). CONCLUSION: Surface pretreatment of the acrylic resin with monomer prior to resilient liner application is an effective method to increase bond strength between the base and soft liner. Sandblasting, on the contrary, is not recommended as it weakens the bond between the two.
Aluminum Oxide ; Collodion ; Denture Bases ; Dentures ; Dimethylpolysiloxanes ; Polymethyl Methacrylate ; Silicone Elastomers ; Tensile Strength