He visited the dental clinic in Bukit Batok on Tuesday afternoon to have his teeth cleaned.
But Mr Eddie Koh Kar Wee said he got more than he bargained for.
The 34-year-old sales manager claims the attending dentist at Q & M Dental Surgery extracted his upper molar without his permission - a procedure that he said not only left him $500 poorer but also bleeding for 22 hours.
However, a spokesman for Q & M Dental Group (Singapore) is denying Mr Koh's allegations.
While the matter is still being investigated, the group's general counsel Mr V Subramaniam told The New Paper in an e-mail yesterday : "Our initial investigations show that the patient has signed a written consent for the extraction of the tooth contrary to the allegations in his e-mail".
Earlier yesterday, Mr Koh sent an e-mail - a copy of which was obtained by TNP - to the company explaining his predicament.
The father of two boys told TNP: "I asked them to clean my teeth but I also told the nurse that there was a crack in my teeth and I wanted the doctor to see if it was all right."
At no time did he give the dentist any permission to extract the tooth, said Mr Koh, who was visiting the clinic in Bukit Batok for the first time.
"The only papers I signed was after the procedure, and that was with the understanding that I was signing papers so I could pay for the visit using my Medisave," he said.
So why didn't he protest during the procedure if he sensed that things were not going according to his wishes, especially since he felt something was - in his own words - "not right" when the dentist injected him with an anaesthetic?
He admits on hindsight that the injection did not seem right when all he wanted was to have his pearlies cleaned.
Still he did not say anything because he said he was unfamiliar with dental procedures.
Mr Koh said that is why attending dentists should have "made an effort" to explain to patients what they were doing.
It was only an hour later that he realised things had taken a different turn.
Upset when he learned that his tooth had been pulled out, Mr Koh said he demanded an explanation.
"After stitching the wound, the dentist told me to come again for another appointment," he said.
"I told her before I left, if it was important to have the tooth pulled out she should have told me.
"But she told me after the procedure I should have told her I didn't want it... but like I said, I did not know what was going on," he added.
Mr Koh left the clinic at 5pm after being told that the swelling and bleeding would stop "in three hours".
But it was not the case. He said he spent the whole of Tuesday night in pain.
"The bleeding didn't stop and at 3am my wife sent me to Singapore General Hospital's emergency department to see a doctor," said Mr Koh.
""They gave me medicine to control the bleeding and sent me home," he added.
While he said he is still in pain, the bleeding stopped completely yesterday.
When informed about this, Q & M Dental Group's Mr Subramaniam declined to comment.
In the e-mail sent to TNP, the group said it "will fully investigate the matter and interview our dentist and clinical assistant to ascertain the full details."
The results of the investigation is expected to be ready tomorrow, he added.
Mr Koh hopes to get a satisfactory answer from the clinic.
"My problem here is that I was bleeding for 22 hours after the tooth was pulled out," he said.
"I'm disappointed because all I wanted to do was have my teeth cleaned."
This article was first published in The New Paper.