Written by Bart McFarland, DMD Monday, 30 June 2003 19:00
Dental care is changing to meet the needs of today’s patients’ lifestyles. For example, taking off from work to repair a tooth is a problem in our fast-paced society. This article describes a case where laser and CAD/CAM technologies were combined to provide a patient with endodontic and restorative treatment in a single visit. The use of such modern technologies not only makes dentistry more efficient and convenient for the patient but can increase profitability for the dentist as well.
The patient was a 30-year-old female who presented with symptoms of pain on percussion, pressure, and thermal changes involving tooth No. 29. The tooth also exhibited periodic pain with no stimulus. The radiograph showed no periapical pathology or bone loss. The patient had lost tooth No. 30 and had a residual root tip in that area. Tooth No. 29 had no periodontal disease. It was determined that the tooth could be restored.
|Figure 1. Safe-Mate needle used for injection.||Figure 2. Onlay prep—notice pulp exposure.|
The area was anesthetized with a Safe-Mate needle (Medpro, Figure 1) and 2 carpules of 1:100,000 lidocaine with epinephrine. The X-Tip and 1/2 carpule of Citanest with no epinephrine (DENTSPLY Pharmaceutical) was also used. After profound anesthesia was established, all decay was removed, and the tooth was prepared for an onlay. The walls of the preparation were not divergent but more straight up and down, or convergent (Figure 2). The reason for this type of preparation is the onlay will act more passively, and there is less chance for an open margin with the cavosurface junction. The pulp was exposed and some bleeding was observed, which was stopped with Superoxol (Sultan). Next, the tooth was treated with Procad adhesive medium (Ivoclar Vivadent). A quick burst of air was used to thin the oil. The tooth was then covered with Procad contrast medium powder applied with a Powder Meister. (Thin any clumps of powder with a quick burst of air.)
|Figure 3. Onlay prep with Procad powder.|
The optical impression of the tooth was made with the Cerec 3 (Sirona, Figure 3). The onlay was then designed, and the proper-sized (8 mm) ceramic block (Vitabloc Mark II, Vita) was selected and placed in the milling unit.
|Figure 4. Initial radiograph with No. 15 file in place.||Figure 5. 30-.06 is seated to working length.|
Root canal therapy was initiated. First, a working length was established with a No. 15 file placed, then a digital radiographic image was taken (Dexis, Figure 4). Once working length was established, the canals were irrigated with a mixture of 50% chlorhexidine gluconate (Prodentx) and 50% sodium hypochlorite (Sultan) placed in the canals with a 30-gauge, 25-mm-length Max-i-Probe side port needle (DENTSPLY MPL). The irrigation solution was used between each file to flush and produce a bactericidal effect.
The canal was enlarged to a size 20 file to determined length. A NiTi rotary file system (ProfileGT, DENTSPLY Tulsa Dental) was used to both enlarge and shape the canal. The canal was enlarged to a 30-.06 file to reach the apex (Figure 5). In each procedure, both hand files and rotating files were coated with Prolube (DENTSPLY Tulsa Dental) before the files were instrumented into the canals.
|Figure 6. Endolase being placed in the canal and withdrawn.|
The Waterlase laser (Biolase) was used with a Z2 25-mm endo tip (Endolase), with the tip placed in the canal 2 mm from the apex. The laser was then fired for 15 seconds at 1.50 W, 24% water, and 34% air each time the endo fiber was withdrawn at different sections of the internal walls. (Figure 6) This has 2 functions: (1) cleaning and shaping of the internal walls, and (2) sterilizing or creating a bactericidal effect on the inside of the tooth. The endo fibertip was placed and withdrawn 3 times for 15 seconds each with the laser fired constantly until it exited the tooth. The canal was irrigated and dried with the 30-gauge Max-i-Probe needle placed on the suction surgical tip. The needle was placed in the canal with the suction activated. The fluid in the canal was suctioned out through the Max-i-Probe. The rest of the fluid in the canal was dried with medium and fine absorbent paper points (Henry Schein).
There is an alternative technique option that works well with the Endolase. Starting with the Z-2 tip 2 mm from the apex at 1.50 W, 24% water, and 34% air, fire the laser as you retrieve from the apex to the cervical area for 8 seconds per sequence. Aim the tip at one portion of the canal wall, moving the fiber tip along one segment of the lumen of the canal. Repeat the same process at a different portion of the lumen. The Z-2 tip is fired a total of 6 times, then the Z-3 tip is used in the same manner. If you cannot accommodate the Z-3 tip after one sequence with the Z-2, you may repeat with Z-2 until you can fit Z-3 to 2 mm from the root end. Then the Z-4 is used in the same manner. After this sequencing of laser firings, you should be able to fit a 35 K file to working length.
The root canal is obturated with Thermaseal Plus (DENTSPLY Tulsa Dental), which is placed on a size 20 file and inserted into the canal, rotated counterclockwise, and placed on all parts of the internal walls. Gutta-percha size 30-.06 (GT Obturator, DENTSPLY Maillefer) is used to obturate the canal because it corresponds with the rotary file that is first to reach the apex of the tooth. The 30-.06 is heated in a timed oven (Thermaprep Plus, DENTSPLY Tulsa Dental) and placed into the canal to the predetermined stopper on the obturator.
|Figure 7. Final x-ray after Thermafil has been placed.|
The final radiograph was taken. (Figure 7) The plastic carrier was cut off at the orifice of the canal. The gutta- percha can be removed coronally to a depth of 2 mm inside the canal so the root canal can be sealed with Panavia cement (Kuraray). Retention and the seal will be greater if cement is placed down inside the canal. The onlay preparation was air- abraded with 50-µm aluminum oxide particles to remove debris and increase retention.
|Figure 8. Onlay after retrieval from Cerec milling unit.|
The onlay was retrieved from the milling unit (Figure 8), tried in, and the contact adjusted with an egg-shaped fluted bur (SS White FG-7008). For bonding, the Panavia cement system was used. The onlay was steamed for 10 to 15 seconds to remove all oils and contaminates, then treated with Vita Ceramic Etchant for 60 seconds. The etch was rinsed off, and 2 coats of Porcelain Primer Silane (Bisco) were applied. A No. 1 tofflemire matrix band (HO Band 0.001 regular) was placed around the prepared tooth. The Panavia Primer A&B was mixed in a mixing well and placed on the tooth for 60 seconds with a Microbrush (Microbrush), then air-dried. Next, the color of the cement was selected, and dual cement was mixed and placed in a CR tube and plug, which is light-resistant so the cement will stay inside the tube for 5 to 6 minutes before it starts to cure. The tube was then inserted into a Nugun (Centrix). The cement was placed into the matrix to the top of the preparation and matrix band. The onlay was seated and held firmly in place with a composite instrument while some excess cement was removed. With continuous, firm pressure on the onlay, it was light-cured for 15 seconds (Virtuoso, Rembrandt), then the matrix was removed with the Wynman Crown Gripper (Miltex).
|Figure 9. Onlay seated and polished.|
The onlay was immediately flossed to make sure no cement was in the contact area. The occlusion was adjusted with a round coarse bur (NeoDiamond, Microcopy). The buccal and lingual surfaces were adjusted with a medium coarse tapered diamond (Brasseler 855-021). Next, the occlusal, buccal, and lingual surfaces were smoothed with a round, 12-fluted carbide bur (Brasseler fg-7008). The final polish was accomplished with Enhance finishers (DENTSPLY Caulk), and the ceramic sludge was retrieved from the milling unit. After the polishing was completed, the restoration was flossed and the occlusion was checked a final time with Markrite articulating ribbon (Holg Mfg.) (Figure 9).
This procedure was accomplished easily in one appointment in approximately the same amount of time it usually takes to complete an onlay alone. The combination of laser and CAD/CAM technologies in this case allowed the practitioner to be more efficient, predictable, and patient-friendly.
Dr. McFarland received his doctorate in dental medicine from the University of Kentucky. He maintains a private practice in Paris, Ky, with an associate. He has had the Cerec machine for 2 years and has placed approximately 2,000 restorations. He has recently been using the Waterlase combined with the Cerec machine. He also specializes in computerized dentistry. He can be reached at (859) 987-4775.
- Clinical Update
- CE Articles
- Dental Materials
- Dental Medicine
- Digital Impression Technology
- Forensic Dentistry
- Geriatric Dentistry
- Infection Control
- Interdisciplinary Dentistry
- New Directions
- Practice Management
- Oral Cancer Screening
- Oral Medicine
- Oral-Systemic connection
- Pediatric Dentistry
- Pain Management
- Post-and-Core Technique
- Sleep Disorders
- Sports Dentistry
- Technique of the Week
- Treatment Planning