Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Happy teeth

Our teeth are feeling very clean and gums very tingly. Love the massage and tongue cleaning speed features. Two problems: [1]If you do not hold the main handle correctly [lower than I feel comfortable with], you inadvertently turn the action off by pushing the control button [2] Somehow the flip to cover over the brush head storage compartment came off and I had to reassemble the plastic post, spring, and push the cover back onto the compartment.