Abstract: An adapter for mounting the end of a toothbrush handle to the vibratory output shaft of a toothbrush motor is a generally cylindrical body having front and rear bores for respectively receiving the handle and the shaft. The body is a resilient plastic molded about a cup-shaped metal insert. The interior surface of the insert defines the rear bore and includes roughening projections for engaging the shaft. The exterior surface of the insert appears as a pin recessed coaxially in the front bore for engaging a bore in the end of the toothbrush handle. The front bore is defined by plural angularly spaced apart plastic fingers configured to snap into a circumferential groove in the toothbrush handle.