I heard augmentin (amoxicillin and clavulanate) is combined of amoxicillin and some acid. is it possible for someone amoxicillin works abit but not augmentin (amoxicillin and clavulanate) for tooth infection?

Augmentin (amoxicillin and clavulanate): is really "super-amoxicillin" and contains a chemical, potassium clavulanate, which make it even more effective for treating infection.

Antibiotics: Resolution of a tooth infection usually requires treatment of the cause of the infection as well as the use of antibiotics. Which antibiotic to use as well as the dosage and frequency varies from individual to individual and from case to case. Your own dentist can prescribe the proper course of antibiotics and monitor its effectiveness.

Augmentin (amoxicillin and clavulanate) is good: It is commonly used for dental infection and abscesses. Clavulanic acid dissolves the outer membrane of the bacteria if the bacteria has developed some resistance to amoxicillin. Anyway, if you do have a tooth infection, you really need to see a dentist for a definitive treatment.

No: It is possible though that Augmentin (amoxicillin and clavulanate) can help where Amoxicillin hasn't been effective for tooth infection.