Dental [ and surgical ] machines and apparatus, namely, dental handpieces, [ surgical dental handpieces, ] air motors for dental handpieces, [ air motors for surgical dental handpieces, ] micromotors for dental handpieces [, micromotors for surgical dental handpieces; dental polishing, cleaning, and cutting instruments, namely, air scalers for dental use, ultrasonic scalers for dental use, ultrasonic cutters for dental use; ] dental instruments for measuring root canal length