For many people, the dental office is the place where nightmares are lived out, but a new laser instrument may make the dental office less of a grim experience.

People who hate the dental office will love the laser. The little hot beam of light that cauterizes the tissue results in a surgery is less painful than one with the cold steel scalpel, dentists say.The laser is not a new invention. Gynecologists, plastic surgeons and colon-rectal surgeons have been using it for surgical purposes for many years. Now dentists are calling it the wave of the future in high-tech dentistry.

"Lasers are bound to become the tool of the future," said Leo Miserendino, D. D. S, an assistant clinical professor at Marquette University Dental School in Milwaukee. Miserendino, an endodontist, also has been researching the use of lasers in hard tissue surgery, which includes tooth decay and root canals.

"You can do things with a laser you can't do with a scalpel, like go around corners to remove tissue. Certain areas of the mouth are just very difficult to get to with a scalpel," he added.

There are some drawbacks to the high-tech wand. The cost of the laser to the dentist is staggering, running about $25,000.

Richard Mungo, D.D.S., head of division pediatric dentistry at Childrens Hospital of Los Angeles, said the laser "would be the most expensive piece of equipment in the dentist's office."

Mungo, who has a private practice in Huntington Beach, is one of the few dentists in the Southland using a laser. He also conducts training seminars on the use of lasers at Childrens Hospital.

According to the Academy of General Dentistry in Chicago, fewer than a dozen dentists with general practices have laser equipment.

In addition to the cost, another limiting factor is its size. "It's huge, very smiliar to the old computers in the 1950's," Mungo said.

"It could fill up a room. At that cost and at the size, it's impossible to think of using it in the office." Mungo said that most of the laser equipment is found in the operating rooms of hospitals.

"More compact units are in development," Mungo noted. "Pfizer Laser Systems (a division of Pfizer Inc.) in Irvine has one the size of a typewriter. Other companies have lasers that look like (the "Star Wars" robot)R2D2."

Safety is another concern. Miserendino said patients must put a damp gauze on their eyes and face, and their body must be covered with a surgical robe to protect them from being unintentionally burned or cut by a stray laser beam.

Patients also have the option of wearing glasses to protect their eyes, Mungo said.

Although Mungo teaches a course that offers a certificate to those who successfully pass it, he said dentists are not required to be certified to use the laser.

"The laser isn't a panacea," said Mungo. "It's not God's gift to surgery. It's a new technique. It's a new instrument. But surgeons should not abandon proper surgical techniques."

The number of dentist who are using the laser is expected to grow rapidly over the next five to 10 years, according to Robert Pick, an assistant clinical professor of periodontics at Northwestern University's Dental School in Chicago and a pioneer is soft-tissue surgery with the laser.

Pick, who uses a laser in his private practice in Chicago, said laser has advantages over the traditional surgical methods because the laser cuts precisely and does not disrupt nearby tissue, leaving little scar tissue.

This helps decrease the patient's post-operative pain and the possibility of infection, according to Miserendino.

But what dentists are the most excited about is that the laser coagulates blood vessels resulting in a nearly blodless surgery. Because there is so little blood, this minimizes the spread of infectious diseases, Miserendino said.

The laser sterilizes the area and causes little post-surgical pain, according to Pick, who addes that 90 percent of his patients did not require a narcotic analgesic for post-operative pain, although some did report having a sore throat the first night after surgery.

Pick said the laser can be used to remove lesions in the mouth, including tumors.

The cost of laser surgery is similar to that of conventional methods, he said, and most dental insurance policies will cover laser procedures.

oAda oiov ly n President Chun Doo-hwan hurled hundreds of firebombs Friday at riot police in street clashes after authorities blocked a protest march.

Radicals battled police in streets and alleyways around Dongguk University in eastern Seoul about some 2,000 students from 10 Seoul colleges tried to march out despite freezing temperatures. About 1,000 protesters stormed out of the college to bombard troopers with rocks and firebombs that exploded in showers of blazing gasoline.

"Arrest Chun Doo-hwan," protesters shouted. "Yankee go home."

Several thousand riot police in green combat fatigues and black visored helmets ringed the campus to stop students breaking through. Troopers fired volleys of choking tear gas and hurled back rocks and other missiles.

Police had no immediate word on casualties or arrests.

Student leaders at an earlier campus rally denounced Chun's apology on Wednesday for corruption and human rights abuses. Leaders demanded the former president be arrested and prosecuted for numerous alleged crimes.

Protesters also denounced President Roh Tae-woo and demanded he also be punished.