I reached out to Dentsply Sirona who manufacturers Cavitrons. I was told that the most damage and problems they see with Cavitron units is from using inserts that are not manufactured by Dentsply Sirona:
 
Though inserts from a different manufacturer than the ultrasonic unit appear the same, there is high variability and significant differences which can damage an ultrasonic unit and affect treatment outcomes.1,2 Research shows using inserts from a differing manufacturer than the unit increases the displacement amplitude with an increase in power setting.1 Displacement amplitudes of inserts from different manufacturers are found to be significantly different from each other at all loads.1 In addition, insert movement varies between different manufacturers.2 This variability is most often the cause of damage to an ultrasonic unit. Using inserts from the same manufacturer as the ultrasonic unit guarantees effective treatment outcomes without compromising or damaging the ultrasonic unit.
 
1. Lea, S.C., Landini, G., Walmsley, A.D. Ultrasonic Scaler Tip Performance under Various Load Conditions. J Clin Periodontol. Oct. 2003; 30(10):876-881.
2. Lea, S.C., Landini, G., Walmsley, A.D. Displacement Amplitude of Ultrasonic Scaler Inserts. J Clin Periodontol. Jun. 2003; 30(6):505-510.
 
They said it could be so many things that it would be best if you called them directly at:
1-800-989-8826, Monday through Friday, 8:00 A.M. to 5:00 P.M. (Eastern Time)