You could try using a lower value resistor pull-up of 3.33k to limit the current flow to the pin to approximately 1 mA. The 4.7k resistor which comes with some DS18B20 sensors was intended for 5V boards.
Another thing to try would be to increase the clocking speed in setup():
Wire.setSpeed(CLOCK_SPEED_400KHZ);//set the I2C clock speed to 400Khz