Dental centre sinks teeth into 3-D moulds

Samples of 3-D digital orthodontic models of patients' teeth that are now being used in place of plaster moulds at the National Dental Centre Singapore. -- PHOTO: NATIONAL DENTAL CENTRE SINGAPORE
Samples of 3-D digital orthodontic models of patients' teeth that are now being used in place of plaster moulds at the National Dental Centre Singapore. -- PHOTO: NATIONAL DENTAL CENTRE SINGAPORE
(Above) Samples of 3-D digital orthodontic models of patients' teeth that are now being used in place of plaster moulds at the National Dental Centre Singapore. (Left) A patient getting a 3-D dental scan done.
(Above) Samples of 3-D digital orthodontic models of patients' teeth that are now being used in place of plaster moulds at the National Dental Centre Singapore. (Left) A patient getting a 3-D dental scan done.PHOTOS: NG SOR LUAN, NATIONAL DENTAL CENTRE SINGAPORE

Plaster moulds on the way out, saving time and space

PLASTER moulds of teeth that are made for every patient who needs to have braces fitted, and then stored for years, are set to be a thing of the past.

The National Dental Centre Singapore has, since May, been producing 3-D scans of patients' teeth in place of full-sized plaster casts.

Some 4,000 patients have gone down this electronic route. Separately, thousands of moulds belonging to former patients have also been archived in a database. Not only are the digital images easier for dentists to analyse, it also helps to free up space in the public institution.

Some 90 per cent of the plaster moulds at the centre have been destroyed, while the rest are estimated to go within a year.

The plan is to use the space for a new clinic, said Dr Chew Ming Tak, director of the dental centre's orthodontics department.

The centre fits braces for about 1,500 new patients every year. Usually, two sets of teeth moulds are done for each patient - before and after wearing braces. The moulds help dentists to plan the course of treatment, as well as to explain to patients what their problem is.

But the bulky casts have to be stored for decades, even after the patient has completed his treatment, said Dr Chew, adding that casts sometimes get misplaced or even damaged.

In the past, tens of thousands of casts used to be stacked on shelves "up to the ceiling", said Dr Chew. "The records office was getting impossible to walk through," he said. "We had to look for digital solutions, to transform the plaster moulds into 3-D images."

The centre now sends simple plaster models, made in the clinic, to an external vendor, which will scan and convert them into high-resolution digital formats. After scanning, the plaster models are destroyed. The digital moulds are remotely uploaded into a server, to be easily accessed by multiple users. The process now takes two to three days, compared with one week for making plaster casts.

Dentists can also do more with the digital images. For instance, computer software allows them to make more precise measurements. They can also conduct simulations to see how different treatment plans will pan out.

Previously, dentists could only use a saw to "painstakingly" cut up plaster moulds and forge the parts back together with wax "to see if they fit", said Dr Chew.

Surgeon Lye Kok Weng said the dental centre is looking into further simplifying the process - by generating the 3-D images using a scanner to obtain information inside the mouth.

Beyond braces, jaw surgery conducted at the centre now also taps 3-D scanning and printing technology. Before, surgeons used mainly flat images like X-rays and photographs.

Patients also had to sit for a two-hour session in which surgeons laboriously measured and recorded the data of their facial and jaw structure. In contrast, a 3-D scan takes less than one minute.

The technology also helps surgeons to plan the surgery and predict results better, said Dr Lye, an oral and maxillofacial surgeon at the dental centre.

Every year, the centre performs jaw surgery for up to 150 patients. Over the past two years, surgeons have used 3-D technology for about 50 to 60 patients with complex jaw deformities.

"With this new method, we have a digital face we can look at anytime, without having to ask the patient to come in," said Dr Lye.

chpoon@sph.com.sg