See Computer Security.
Embezzlement is a serious problem that affects many dental offices. The risk is especially high because dentists frequently fail to put mechanisms in place to prevent it. Embezzlement can definitely be prevented. Prevention must pervade the entire office atmosphere and involves many related strategies. Here are some suggestions to get you started.
Don't hire someone who has bad credit, criminal history, or drug problems. Run a credit report, criminal check, and drug test. Let it be known that you expect all staff to maintain good credit and that there might be random drug testing. Theft is very frequently tied to a need to pay for a drug habit or related to personal financial difficulties. Help the staff learn how to handle their personal finances.
Back up Open Dental, and keep copies of backups at home. Run an annual financial report from last year, and compare it to the same report on the backup. There should be no change. Do the same for the previous month, and for the previous day. Let it be known that you do this. This prevents staff from altering history and lets you catch them if they do. Staff have been known to go so far as to purposely destroy the current working copy of the office database in order to cover their tracks. They have been known to enlist a spouse who has high technical skills in order to assist with things like this.
Turn on the security features of Open Dental. Create two users for yourself, one for routine usage, and one for admin. That way, if you leave your regular user up when you leave your private office, someone can't walk in and alter anything. Keep passwords private. Don't write down your private password anywhere at the office, and insist on everyone looking away every time you log in. Review the security logs and challenge staff on certain historical changes just to let them know that you're watching.
Two staff should be involved in every critical financial function, like making cash deposits. Make them alternate. Make them work together. Anything. Make it so that they would have to collude in order to embezzle.
Sneak an odd amount of money into the cashbox, and see if they report it or pocket it. If they pocket it, fire them. If you want to be more fair about it, you can make it well known that you intend to randomly add or remove cash from the cashbox to keep them honest. Staff frequently "borrow" money from cashboxes. So don't give them too much control over it. Make them aware that you have the key and that you count it periodically. Consider getting rid of the cashbox, not offering change to patients, and requiring deposit of all cash every evening.
Review every deposit and sign every check. Do not delegate those functions.
Require staff to give a receipt for every cash payment. A common petty trick that is used by staff is to pocket cash payments. They must then figure out how to alter the patient account so that the patient won't complain. Sometimes, they do this by adding an adjustment, or sometimes by lowering a fee for a procedure. Look for this behavior in the audit trail.