A Maryland malpractice arbitration panel has awarded a record $670,000 to a man who lost nearly half his lower jawbone because a Bethesda oral surgeon failed in five attempts to remove a tumor in what should have been a single operation, the patient's attorneys said yesterday.

The patient, a 29-year-old Washington County man, will face repeated surgeries for years to come, one of the attorneys said.

The award, announced yesterday in a negligence case involving Dr. Lloyd E. Church, 67, is the largest against a dentist since the state's malpractice arbitration system was established in 1976, according to Walter Tabler, director of the Maryland Health Claims Arbitration Office, which administers the system.

Church, who practices at 4853 Cordell Ave., has not been cited for malpractice in the 11 years since the office came into existence, but was reprimanded in 1985 for making sexual remarks during a physical examination of a disrobed female patient, according to Larrie Bennett, director of the State Board of Dental Examiners. Church has been a dentist since 1944.

From 1978 to 1984, Church performed five operations on Stephen Spurrier to remove a benign tumor growing inside Spurrier's lower jawbone. But Church left part of the tumor behind after each operation, the arbitration panel concluded.

One of Spurrier's attorneys, Dr. Dwane DeVore, who is also a professor of oral surgery at the University of Maryland, said in an interview that the tumor eventually destroyed a five-inch section of Spurrier's jaw, beginning just below his left ear.

An oral surgeon replaced the five-inch section with part of one of Spurrier's ribs, DeVore said.

But any human bone grafted into a patient's jaw will eventually deteriorate, DeVore said.

He added that Spurrier will require a similar operation every three to five years.

In time, he said, the accumulation of scar tissue may preclude further transplants. DeVore said that would leave Spurrier with a deformity and impair his ability to eat and speak, among other problems.

Spurrier said last night that he was pleased by the verdict but braced for long appeals by Church. "I forgive him," he said.

"The reason we pursued this is that we wanted some answers about what happened."

Church, whose resume shows he graduated from the University of Maryland dental school in 1944, denied any wrongdoing in an interview but would not comment further on the $670,000 award, saying he had not seen the three-member panel's written decision.

Church's attorneys argued to the arbitration panel that the dentist removed the entire tumor after the first operation and it continued to grow back.

His attorney, Robert Goodson of Washington, after the ruling would say only that "my client disagrees with the findings of the panel" and is contemplating an appeal in Montgomery County Circuit Court.

The malpractice ruling, Bennett said, does not place Church in danger of losing his license to practice.

The reprimand against Church for "unprofessional behavior" two years ago stemmed from a physical examination of a female patient, Bennett said.

He said the board found that Church "exceeded the scope of the physical examination required, posed unnecessary and inappropriate questions during the examination, made unnecessary comments such as, 'How is your lovemaking?' and asked the patient to kiss him upon leaving the office."

Church's resume shows he completed a residency in oral surgery at the Medical College of Virginia Hospitals in Richmond in 1946. Bennett said the board recognizes that oral surgeons sometimes must perform physical examinations before treating patients, but requires they do it "in a hospital setting," not in an office.

Bennett said the Health Claims Arbitration Office is required by law to report malpractice complaints to the Board of Dental Examiners, but the board normally undertakes an investigation of a dentist only after it notices a pattern of allegations.

The board has revoked 10 licenses and suspended 14 others in the last three years, he said, but most of those dentists were accused of committing insurance fraud.