Effect of impression coping and implant angulation on the accuracy of implant impressions: an in vitro study

PURPOSE: The purpose of this study was to compare the accuracy of the implant master cast according to the type (pick-up, transfer) and the length (long, short) of the impression copings. MATERIALS AND METHODS: The metal master cast was fabricated with three internal connection type implant analogs (Osstem GS III analog), embedded parallel and with 10degrees of mesial angulation to the center analog. Four types of impression coping were prepared with different combinations of types (transfer, pick-up) and lengths (long, short) of the coping. The impressions were made using vinyl polysiloxane (one step, heavy + light body) with an individual tray, and 10 impressions were made for each group. Eventually, 40 experimental casts were produced. Then, the difference in the distance between the master cast and the experimental cast were measured, and the error rate was determined. The analysis of variance was performed using the SPSS (v 12.0) program (alpha = .05), and the statistical significance was set at P < .05. RESULTS: The ANOVA showed that the pick-up type impression coping exhibited a significantly lower error rate than the transfer type. However, no significant difference was observed with respect to the length of the impression coping. Additionally, no significant difference was observed between the parallel and mesial angulated groups. CONCLUSION: Within the limitations of this study, the pick-up type impression coping exhibited a more accurate implant master cast than the transfer type in parallel group. The accuracy of the implant master cast did not differ for different lengths of impression coping of at least 11 mm. Additionally, the accuracy of the implant cast was not different for the parallel and 10degrees mesial angulated groups.

Effect of etching time on shear bond strength of resin cements to reinforced all-ceramic crowns / 대한치과보철학회지

PURPOSE: The purpose of this study was to evaluate the effects of etching time on shear bond strength of four resin cements to IPS Empress 2 ceramic. MATERIAL AND METHODS: Forty rectangular shape ceramic specimens (10x15x3.5mm size) were used for this study. The ceramic specimens divided into four groups and were etched with 10% hydrofluoric acid for 0, 10, 30, 60, 180, 300, 420, 600, and 900 seconds respectively. Etched surfaces of ceramic specimens were coated with ceramic adhesive system and bonded with four resin cement (Variolink II, Panavia F, Panavia 21, Super-Bond C & B) using acrylic glass tube. All cemented specimens were tested under shear loading untill fracture on universal testing machine at a crosshead speed 1mm/min; the maximum load at fracture (kg) was recored. Shear bond strengh data were analyzed with oneway analysis of variance and Tukey HSD tests (p<.05). Etched ceramic surfaces (0-, 60-, 300-, and 600-seconds etching period) and fracture surfaces after shear testing were examined mophologically using scanning electron microscopy. RESULTS: Ceramic surface treatment with 10% hydrofluoric acid improved the bond strength of three resin cement except for Super-Bond C&B cement. Variolink II (41.0+/-2.4 MPa) resin cement at 300-seconds etching time showed ststistically higher shear bond strength than the other resin cements (Panavia F: 28.3+/-2.3 MPa, Panavia 21: 21.5+/-2.2 MPa, Super-Bond C&B: 16.7+/-1.6 MPa). Ceramic surface etched with 10% hydrofluoric acid for 300 seconds showed more retentive surface texture. CONCLUSION: Within the limitation of this study, Variolink II resin cement are suitable for cementation of Empress 2 all-ceramic restorations and etching with 10% hydrofluoric acid for 180 to 300 seconds is required to enhance the bond strength.

Effects of Verapamil Combined with Esmolol on Blood Pressure and Heart Rates during Tracheal Intubation / 대한마취과학회지

BACKGROUND: Antihypertensive agents such as verapamil and esmolol are well known for their effects of hemodynamic stabilization on tracheal intubation. However, our previous study, Verapamil and esmolol did not attenuate heart rate and blood pressure. The aim of the present study was to evaluate the efficacy of combined administration of these drugs for controlling hemodynamic responses to tracheal intubation. METHODS: Forty-eight patients, ASA physical status I or II, were randomly assigned to one of four groups (n = 12 each):normal saline (control), verapamil 0.1 mg/kg, esmolol 1 mg/kg, and verapamil 0.05 mg/kg mixed with esmolol 0.5 mg/kg. Anesthesia was induced with thiopental 5 mg/kg intravenously, and then saline, verapamil, esmolol or the mixed drugs were administered as an intravenous bolus, and immediately followed by succinylcholine 1.5 mg/kg. Tracheal intubation was performed 90 s after intravenous injection of experimental drugs. Systolic and diastolic blood pressure and heart rate were measured before induction and every minute for 5 minutes after tracheal intubation. RESULTS: There was a significant attenuation in systolic blood pressure after tracheal intubation in the verapamil and mixed groups compared to the control and esmolol groups. Heart rates were significantly lower in the esmolol and mixed groups than in the verapamil groups after tracheal intubation. CONCLUSIONS: Combined administration of Verapamil 0.05 mg/kg with esmolol 0.5 mg/kg attenuated increases in blood pressure and heart rate after tracheal intubation.

Spontaneous Intracerebellar Hematoma

Twenty-five patients with spontaneous intracerebellar hematoma were analyzed, who had been admitted to Jeonju Jesus Hospital from 1982 to 1985. All cases were diagnosed by CT scan and the amount of the hematoma was assessed by the largest diameter and the height as large, moderated, and small. Three clinical types were defined to evaluate the method of treatment and the outcome. All twelve acute cases were operated and seven were dead-five from brainstem failure, one from rebleeding, and one from chest infection. All chronic cases were treated conservatively to yield good results. Of seven subacute cases, five were operated and two died. Overall mortality was 36% and surgical mortality was 53%. To avoid considerable loss of potential recovery, it is suggested that prompt confirmation of the intracerebellar hematoma by CT scan, emergency surgical management, proper pre-and post-operative care results in better prognosis in cases of this not-uncommon-not-incurable disease.