A mouthpiece assembly for cleaning teeth, comprising: an upper mouthpiece for receiving a first set of teeth from the maxillary dental arch of a user and for simultaneously cleaning multiple tooth surfaces of the first set of teeth , and including an upper channel having two opposite vertical upper walls adapted to extend along side surfaces of the first set of teeth and a central upper wall in between facing horizontal surfaces of the first set of teeth ; a lower mouthpiece for receiving a second set of teeth from the mandibular dental arch of the user and for simultaneously cleaning multiple tooth surfaces of the second set of teeth , and including a lower channel having two opposite vertical lower walls adapted to extend along side surfaces of the second set of teeth and a central lower wall in between facing horizontal surfaces of the second set of teeth ; a bite block housed between the upper mouthpiece and the lower mouthpiece and including a vertical block section having an upper end extending freely through a first opening in the central upper wall and configured to engage at least one tooth of the first set of teeth , and a lower end extending freely through a second opening in the central lower wall and configured to engage at least one tooth of the second set of teeth ; a driving mechanism for driving movement of the upper mouthpiece and the lower mouthpiece to clean the tooth surfaces; and wherein the bite block , the at least one tooth of the first set of teeth , and the at least one tooth of the second set of teeth create a static arrangement relative to movement of the upper mouthpiece and the lower mouthpiece when the user bites on the bite block , and wherein movement of the upper mouthpiece and the lower mouthpiece driven by the driving mechanism is uninhibited when the user bites on the bite block . an upper mouthpiece for receiving a first set of teeth from the maxillary dental arch of a user and for simultaneously cleaning multiple tooth surfaces of the first set of teeth , and including an upper channel having two opposite vertical upper walls adapted to extend along side surfaces of the first set of teeth and a central upper wall in between facing horizontal surfaces of the first set of teeth ; a lower mouthpiece for receiving a second set of teeth from the mandibular dental arch of the user and for simultaneously cleaning multiple tooth surfaces of the second set of teeth , and including a lower channel having two opposite vertical lower walls adapted to extend along side surfaces of the second set of teeth and a central lower wall in between facing horizontal surfaces of the second set of teeth ; a bite block housed between the upper mouthpiece and the lower mouthpiece and including a vertical block section having an upper end extending freely through a first opening in the central upper wall and configured to engage at least one tooth of the first set of teeth , and a lower end extending freely through a second opening in the central lower wall and configured to engage at least one tooth of the second set of teeth ; a driving mechanism for driving movement of the upper mouthpiece and the lower mouthpiece to clean the tooth surfaces; and wherein the bite block , the at least one tooth of the first set of teeth , and the at least one tooth of the second set of teeth create a static arrangement relative to movement of the upper mouthpiece and the lower mouthpiece when the user bites on the bite block , and wherein movement of the upper mouthpiece and the lower mouthpiece driven by the driving mechanism is uninhibited when the user bites on the bite block . <EOS>