A comparative study on the initial stability of different implants placed above the bone level using resonance frequency analysis

PURPOSE: This study evaluated the initial stability of different implants placed above the bone level in different types of bone. MATERIALS AND METHODS: As described by Lekholm and Zarb, cortical layers of bovine bone specimens were trimmed to a thickness of 2 mm, 1 mm or totally removed to reproduce bone types II, III, and IV respectively. Three Implant system (Branemark System(R) Mk III TiUnite(TM), Straumann Standard Implant SLA(R), and Astra Tech Microthread(TM)-OsseoSpeed(TM)) were tested. Control group implants were placed in level with the bone, while test group implants were placed 1, 2, 3, and 4 mm above the bone level. Initial stability was evaluated by resonance frequency analysis. Data was statistically analyzed by one-way analysis of variance in confidence level of 95%. The effective implant length and the Implant Stability Quotient (ISQ) were compared using simple linear regression analysis. RESULTS: In the control group, there was a significant difference in the ISQ values of the 3 implants in bone types III and IV (P<.05). The ISQ values of each implant decreased with increased effective implant length in all types of bone. In type II bone, the decrease in ISQ value per 1-mm increase in effective implant length of the Branemark and Astra implants was less than that of the Straumann implant. In bone types III and IV, this value in the Astra implant was less than that in the other 2 implants. CONCLUSION: The initial stability was much affected by the implant design in bone types III, IV and the implant design such as the short pitch interval was beneficial to the initial stability of implants placed above the bone level.

Primary Classic Kaposi's Sarcoma of the Penis in an HIV-Negative Patient

Kaposi's sarcoma (KS) is a multifocal hemorrhagic sarcoma that occurs primarily on the extremities. KS limited to the penis is rare and a well-recognized manifestation of acquired immune deficiency syndrome (AIDS). However, KS confined to the penis is extraordinary in human immunodeficiency virus (HIV)-negative patients. We present the case of a 68-year-old man with a dark reddish ulcerated nodule on the penile skin, which was reported as a nodular stage of KS. We detected no evidence of immunosuppression or AIDS or systemic involvements in further evaluations. In his past medical history, the patient had undergone three transurethral resections of bladder tumors due to urothelial cell carcinoma since 2000 and total gastrectomy, splenectomy, and adjuvant fluorouracil/cisplatin chemotherapy for 7 months due to advanced gastric carcinoma in 2005. The patient was circumcised and has had no recurrence for 2 years.

The effect of autoclave sterilization and reuse of Smartpeg(TM) on the implant stability quotient (ISQ) measurement / 대한치과보철학회지

STATEMENT OF PROBLEM: Resonance frequency analysis is evaluated as the non-invasive and objective method for the evaluation of implant stability and has been increasingly used. It is necessary to evaluate the factors affect the ISQ measurement stability. PURPOSE: This study was performed to evaluate the effect of the autoclave sterilization and reuse of Smartpeg(TM) on ISQ measurement. MATERIAL AND METHODs: SmartPeg(TM) (Integration Diagnostics Ltd., Goteborg, Sweden) of autoclave group (A) was autoclave sterilized 9 times and Smartpeg(TM) of reuse group (R) was reused 9 times. Ten SmartPeg(TM)s were allocated to each group and after each autoclave sterilization and reuse, implant stability quotient (ISQ) values were measured 3 times from the two directions a and b at a right angle. Osstell(TM) mentor (Integration Diagnostics Ltd., Goteborg, Sweden) was used and type 1 (article no. 100353) Smartpeg(TM) was selected according to SmartpegTM reference list. Osstem Implant US II fixture (Osstem Co., Seoul, Korea) in 4.0 mm x 11.5 mm was embedded in the self-curing acrylic resin (Orthojet(R), Lang Dental, U.S.A.). Data was statistically analyzed by one-way ANOVA (alpha= .05) and scheffe test was done where a significant difference exist. Correlation test was also done between ISQ value and the number of autoclave sterilization or reuse. RESULTS: 1. In autoclave group, the means and sd. of ISQ value before autoclave sterilization were 84.97 +/-0.41, 84.93+/-0.74 at direction a and b. There was significant differences between autoclave groups at direction a and b (P=.000). 2. In reuse group, the means and sd. of ISQ value before reuse were 85.40+/-0.62, 85.50+/-0.57 at direction a and b. There was no significant difference between reuse groups at direction a and b (P>.05). 3. There was a weak positive correlation between the number of reuse and ISQ value at direction a and b (gamma=.207 and .246, P<.01). CONCLUSION: Within the limitations of this study, the following CONCLUSIONs were drawn. Till ninth reuse of Smartpeg(TM), the ISQ measurement stability did not be affected. After twice autoclave sterilization of Smartpeg(TM), the ISQ measurement stability was affected.

Strain changes of acrylic resin specimens cured by three curing cycles / 대한치과보철학회지

The acrylic resin was first introduced as denture base materials in 1937 and it is commonly used for denture base fabrication nowadays. Three different curing cycles (Conventional curing cycle, short curing cycle and long curing cycle) and three commercially available heat-activated acrylic resins (Vertex RS, Lucitone 199 and ProBase Hot) were investigated to find the curing cycle and ma-terial that showed the minimum shrinkage of the resin during polymerization process. A brass master mold was fabricated and duplicated by additional silicone impression material. Stone molds were made by pouring of type III dental stone (SILKY-ROCK YELLOW, Whip-Mix, Louisville, Kentucky). It was embedded in the flask. Strain gauge and thermocouple were embedded in the specimen. Strain gauge and thermocouple were connected to signal conditioning amplifier and data was recorded by pre-programmed software. The parameters ESmax (Maximum ex-pansion strain), Sb (Strain measured just before deflasking procedure), Sa (Strain measured just af-ter deflasking procedure) and Sf (Strain measured at the end of the experiment) were measured delta S was calculated from Sb and Sa (delta S=Sb-Sa). In the experiment concerned about materials, the pa-rameters 90-ESmax (Maximum expansion strain measured during early 90 minutes of curing procedure), 180-ESmax (Maximum expansion strain measured from 90 minutes to 180 minutes), Sb, Sa, delta S and Sf were measured and the following conclusions were made. 1. The ESmax value of conventional curing cycle showed the largest value and the 180-ESmax val-ue of Lucitone 199 showed the smallest value. 90-ESmax values showed no significant difference (p<0.05). 2. delta S values of conventional curing cycle showed the positive values. delta S values of short curing cycle and long curing cycle showed the negative values. All three materials cured by conventional curing cycle showed the positive values. 3. The Sf values of long curing cycle and ProBase Hot (cured by conventional curing cycle)showed the smallest values.