Laser-powered HEMI
Planning a hemisection to manage untreatable roots is a minimally invasive option. Performing it with a laser makes it even more so.
According to Souviron and Groh,1 hemisection is a surgical procedure whereby the roots of a tooth are separated and treated as individual teeth; it is used when maintaining the intact tooth is impossible because of gum disease. Reese2 uses this procedure when only one root of a “key tooth” suffers a persistent endodontic failure. Parmar and Vashi3 indicate that tooth resection preserves as much of the tooth structure as possible rather than sacrificing the whole tooth. Bühler4 states that “clinicians should seriously consider hemisection as an alternative for every molar extraction.” Hemisection involves cutting the tooth in half and removing the root and the portion of clinical crown supported by that failing root.
Light vs. drill
The traditional method of treatment for hemisection involves use of the air-driven handpiece, which can create microscopic fractures in the remaining tooth structures and vibration-induced separation of the restoration from the tooth structure. In addition there is a possibility of air embolism at the surgical site. The Waterlase Er,Cr:YSGG laser (Biolase Technology, www.biolase.com) allows nontraumatic removal of the root using laser energy to section the root from the tooth. The laser also can be used to sterilize the surgical site and promote rapid healing.
Case 1 below experienced no vibration during the hemisection, rapid healing due to laser decontamination of the surgical site, decreased trauma to the surgical site, and no postoperative swelling. Case 2 experienced vibrations during surgery, some post-operative swelling and discomfort, and slower healing of the extraction site. A comparison of the two different approaches indicates that use of the laser results in faster healing with less trauma.
Case 1: Laser assisted
This first case report describes the use of the laser to hemisect a failing mandibular molar.
Treatment planning
A 60-year-old female patient presented with a sore tooth that showed a failure of a previous endodontic therapy. She had a complicated medical history and was taking medications for arthritis, asthma, and glaucoma. These medications included Theragran-M, vitamin E (400 IU), glucosamine chondroitin, Medroxypr (10 mg), and Arthricare. Her medical condition was controlled by these medications. There were no contraindications to dental treatment.
Fig. A is a radiograph showing failure of the endodontic therapy. Treatment options included extraction or retreatment, and the patient decided on retreatment of the involved tooth.
(A) View of patient’s previous failed endodontic therapy. Patient decided on retreatment of involved tooth.
Endodontic therapy was successfully completed with no difficulty. The patient had no complications following retreatment.
Fig. B shows the completed retreatment of all canals.
(B) View of complete endodontic retreatment of all canals.
The patient returned six months later complaining of soreness surrounding the same tooth. Examination revealed a fractured mesial root and abscess (Fig. C). The fractured root extended up to the crown, and the tissue over that root was swollen. Bone loss in the furcation had occurred decreasing the radicular bone height.
(C) Six months later, patient complained of soreness surrounding the same tooth. View of fractured mesial root. Patient opted for hemisection.
This change in the patient’s condition necessitated a new discussion of treatment options. Those options for treatment included extraction and placement of a fixed bridge; extraction and an implant followed by placement of a crown; extraction and a removable partial denture; and hemisection of only the involved root. According to Noguera and Russo,5 hemisection is a procedure that involves removing one-half of a tooth and restoring the remaining root as a single tooth. This patient chose the hemisection in order to remove the source of the abscess but keep the clinical crown of the tooth.
Procedure
Before the Waterlase laser was introduced, hemisection was a traumatic procedure that used a highspeed drill with vibration and forced air/water spray. The Waterlase laser uses hydrokinetic energy to “cut” through the tooth structure with no vibration and only a water mist that is not projected under pressure. Fig. D is a photo showing the exposed fractured mesial root and accumulated granulation tissue, and the loss of bone height in the furcation. The laser is positioned so that the sapphire tip is directed toward the junction of the crown with the root in a buccal-lingual direction so that the laser energy separates the fractured root from the crown, leaving a smooth tooth surface under the crown. The exposed opening to the canal or chamber under the crown was filled with a glass-ionomer restorative material. This exposed tooth surface will be above the gingiva following the removal of the mesial root of the tooth.
(D) Exposed fractured mesial root.
Fig. E shows the location of the laser sapphire tip before the separation of the root from the crown.
(E) Laser positioned in a buccal-lingual approach before separation of root from crown.
Fig. F is a post-operative view showing the tooth following removal of the root and initiation of healing and bone regeneration.
Fig. G is a six-month post-operative radiograph showing rapid bone regeneration in the extraction area. This patient’s response to therapy was similar to that reported by Haueisen and Heidemann.6 The patient got complete relief after the hemisection. However, the patient also was advised that the tooth might eventually fail, because of a lack of mesial support for the cantilevered portion of the crown once the mesial root was removed.
(G) Six-month post-operative view shows rapid bone regeneration in extraction area.
Case 2: Highspeed handpiece
In the second case, an air turbine handpiece was used to complete the hemisection.
Treatment planning
A 50-year-old male in good general health was seen for a recare examination. He had swelling over the mesial root of the mandibular left first molar. Fig. H is a radiograph of the endodontically treated tooth. The abscess was connected to a fistula draining into the buccal fold. Examination of the tooth showed that the mesial root was fractured vertically, yet the distal root was intact and functioning.
H() View of mesial-root endodontic failure. The mesial root is fractured vertically, but distal root is intact.
Various treatment options discussed included hemisection of the split root, leaving the crown and distal root in place; or extraction and replacement of the tooth with a fixed bridge, removable partial denture, or implant.
Procedure
After all of the risks, benefits, and alternatives were fully discussed, the hemisection procedure was selected, and treatment was performed using the standard air-driven handpiece to separate the split mesial root from the crown. Normal surgical entry was accomplished using a scalpel and tissue elevator. Following removal of the mesial root, healing was normal with closure of the fistula and bone regeneration to the extraction area. Fig. I is a panoramic radiograph taken before the mandibular left first molar had abscessed. Fig. J shows the treated area after hemisection.
(I) Pre-operative panoramic radiograph.
(J) Post-operative panoramic radiograph.
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References
1. Souviron RR, Groh KR. Glossary of dental terminology. Available at: “http://www.dentalleaders.com/ terms.htm”. Accessed Oct. 18, 2006.
2. Reese TM. Procedures—-Root amputation/hemisection. Available at: “http://reesedds.com/hemirootamp. htm”. Accessed Oct. 18, 2006.
3. Parmar G, Vashi P. Hemisection: A case-report and review. Endodontology 2003;15:26-9.
4. Bühler H. Survival rates of hemisected teeth: An attempt to compare them with survival rates of alloplastic implants. Int J Periodont Rest Dent 1994;14:537-43.
5. Noguera AP, Russo PL. Hemisection and root amputation. Available at: “http://dcendo.com/svchemi.htm”. Accessed Oct. 18, 2006.
6. Haueisen H, Heidemann D. Hemisection for treatment of an advanced endodontic-periodonal lesion: A case report. Int Endodontic J 2002;35:557-72.
Related Links: Posted by dentalproducts.net. Originally published in the November 2006 Dental Products Report. Copyright 1999-2005 Advanstar Dental Communications.
I just want to say , that the most important thing in any treatment of any tooth , is if the tooth restorable ? or non restorable , as I saw from the 1st case here , the distal root has a 1:2 crown to root ratio , after the hemisection , this ratio will be less than that , cause of the bone resorbtion in the socket of extracted mesial roots ,that will effect the bone surrounding the distal root , so this tooth has a very bad prognosis , and should be extracted ..
Thank you very much