Abstract: Semicrystalline polyethylene-2,2?-bifuran-5,5?-dicarboxylate (PEBF) homopolyester or copolyester with up to 5 mole percent isophthalate or up to 2.7 mole percent terephthalate, based on the diacid component, or up to 2.5 mole percent 1,4-cyclohexanedimethanol (CHDM), based on the diol component, prepared by esterifying or transesterifying the diacid and the diol components with a catalyst including about 10 to about 50 ppm wt metal, and polycondensation, wherein the bifuran polyester has an intrinsic viscosity of at least 0.4 g/dL and a semicrystalline melting peak (Tm) with ?Hf equal to or greater than 5 J/g on the second heating ramp.

Abstract: An ultrasonic instrument includes a tip portion, a transducer configured to convert electrical energy into vibrational energy, an acoustic transformer interconnecting the transducer and the tip portion, and a grip portion disposed at least partially about the acoustic transformer. The grip portion is coupled to the acoustic transformer via a resilient nodal coupling at a nodal region of the acoustic transformer. The resilient nodal coupling is configured to provide rotational and axial stability to the acoustic transformer.

Abstract: A magnetostrictive ultrasonic dental scaler is disclosed. The magnetostrictive device comprises an oscillator adapted to provide electrical energy including a current and a voltage signal, a handpiece having a tool tip which vibrates in response to the electrical energy supplied to the handpiece and a control circuit. The control circuit includes a phase detector adapted to detect phase between current and voltage signals and to generate a phase detection signal as a function of the phase. The control circuit also includes a digital signal processor operatively connected to the phase detector. The digital signal processor adapted to process the phase detection signal through a digital loop filter to generate an error signal.

Abstract: A magnetostrictive ultrasonic dental scaler is disclosed. The magnetostrictive device comprises an oscillator adapted to provide electrical energy including a current and a voltage signal, a handpiece having a tool tip which vibrates in response to the electrical energy supplied to the handpiece and a control circuit. The control circuit includes a phase detector adapted to detect phase between current and voltage signals and to generate a phase detection signal as a function of the phase. The control circuit also includes a digital signal processor operatively connected to the phase detector. The digital signal processor adapted to process the phase detection signal through a digital loop filter to generate an error signal.

Abstract: The invention provides a method of operating a dental scalar system having a vibrating scaling tip by continuously monitoring the amplitude and frequency of vibration of the tip which provides scaling power to a tooth in a patient's mouth. The amplitude and frequency of vibration of the tip is continuously adjusted to maintain a substantially constant scaling power. Preferably, the insert is vibrated at its resonant frequency and the system provides a substantially constant tip motion while the user varies the applied pressure between the tip and the tooth.