Separation to Save a Tooth: Bicuspidization

Abstract

Iatrogenic furcation perforations can occur during root canal treatment or preparing a canal for a post. Furcal- floor may also be perforated accidentally during access opening. Perforations of the furcal-floor mostly cause inflammation in the furcation region and reduce the prognosis of the involved tooth. Through bicuspidization a single molar tooth can be converted into two bicuspids. If both the roots are to be retained, there should be a considerable spread between them for restorative procedures to be successful.

KEY WORDS:molar tooth, bicuspidization, root resection.

INTRODUCTION

Root canal treatment usually fails when treatment is not upto acceptable standards. The reason many teeth do not respond to root canal treatment is because of procedural errors that prevent the control and prevention of intracanal endodontic infection1.Iatrogenic furcation perforations can occur during root canal treatment or preparing a canal for a post. Furcal- floor may also be perforated accidentally during access opening. Perforations of the furcal-floor mostly cause inflammation in the furcation region and reduce the prognosis of the involved tooth 2. If the furcation region is not invaded with any filling or root sealant material, the perforation may be repaired using a hermetic and biocompatible sealant. However, if the furcation region is also irritated with root sealant or other filling materials, surgical access may be required in order to remove the irritants under the fornix. Furcations are the limited regions for adequate access and for removing the irritants from the area with non-surgical procedures3,4. Through bicuspidization a single molar tooth can be converted into two bicuspids. If both the roots are to be retained, there should be a considerable spread between them for restorative procedures to be successful5,6,7.

INDICATIONS FOR BICUSPIDIZATION ARE FOLLOWING

1. Root fracture Severe bone loss affecting one or more roots untreatable with regenerative procedures
2. Class II or III furcation invasions or involvements
3. Inability to successfully treat and fill a canal
4. Severe root proximity inadequate for a proper embrasure space
5. Root trunk fracture or decay with invasion of the biological width

CONTRAINDICATIONS INCLUDE

1. Poor oral hygiene
2. Fused roots
3. Unfavourable tissue architecture
4. Retained roots endodontically untreatable

A multidisciplinary treatment procedure includes restorative dentistry, endodontics, periodontics, and prosthodontics is necessary to preserve the teeth in whole or in part . These teeth can act as independent single units of mastication or as abutments in simple fixed bridges. Hence, tooth resection measures are employed to preserve maximum tooth structure rather than sacrificing the whole tooth. This clinical report cum literature review is a follow up of multidisciplinary treatment procedure for periodontically severed mandibular molar by bicuspidization and total rehabilitation using the double crowns technique. Bicuspidization of affected molars their consecutive prosthetic rehabilitation yielded a satisfactory result4.

CASE DISCUSSION

A 25 year old female patient reported to the department with the chief complaint of pain in the lower left posterior tooth previously treated by root canal therapy two months back.Dental history stated that the tooth had been treated by a general dental practitioner with root canal therapy started 2 months ago.4 days back the patient had noticed an acute pain and intraoral swelling that progressed to become apparent extraorally. There was submandibular swelling over the left side of her mandible on extraoral examination. On intraoral clinical examination, the tooth was sensitive to percussion and the buccal gingival region was edematous and red. The tooth was revealed as Grade II furcation involvement and Grade I mobility. Baseline scores of plaque index PI and gingival index GI were measured at the involved tooth using a Williams type periodontal probe. Radiographic examination showed the furcation area was involved during access opening Fig1. The interradicular alveolar bone was destroyed under furcation fornix depending on inflammation. However, there was no periapical lesion related with mesial and distal roots. Root canal treatment and subsequent bicuspidization was planned in this case. Accordingly access cavity was modified and the working canal length was determined Fig 2 and the canals were biomechanically prepared using crown down technique. Lateral condensation technique was followed in the mesial and the distal canal for obturation Fig 3.

Pre Operative	Working Length Determination

A long shank straight fissure diamond point was used to make vertical cut toward the bifurcation area. Single molar is now separated in two crowns. Constant radiographic monitoring was continued during the separation procedure to save the interradicular bone from unnecessary trauma from bur Fig 4. The furcation area was trimmed slowly to ensure that no residual debris were present that could cause further periodontal irritation. Curettage of the furcation area was done, which became accessible on separation. Damaged tooth structure was reconstructed with composite resincore Fig 5. The occlusal table was minimized to redirect the forces along the long axis of each root and two separate crowns were placed on mesial & distal half of the tooth. Case was followed up postoperatively. After 1 week two separate crowns were prepared Fig6 and impression was taken followed by two separate temporary crowns. After two months follow up patient was recalled and repoted completely asymptomatic. Temporary crown was then removed and final impression was taken with rubber base impression material Fig 7. The patient was delivered with two separate porcelain fused metal crowns to obtain two single-rooted teeth for crowning as premolars Fig 8.

Post Obturation	Bicuspdization Done

Fig 5	Fig 6

Fig 7	Fig 8

DISCUSSION

Root-resection therapy is a treatment option for molars with periodontal, endodontic, restorative, or prosthetic problems. Because root resection is the furcation area was trimmed to ensure that no residual debris were present that could cause further periodontal irritation. Scaling and root planning of the root surfaces, which became accessible on separation was done. Flap was repositioned and sutured very technique-sensitive & complex, proper case selection is essential.9

Farshchian and Kaisar4 stated that the success of Bicuspidization depends on three factors:

• Stability of, and adequate bone support for the individual tooth sections.
• Absence of severe root fluting of the distal aspect of the mesial or mesial aspect of the distal root
• Adequate separation of the mesial and distal roots, to enable the creation of an acceptable embrasure for effective oral hygiene.

According to Newell, the advantage of the amputation, hemisection or bisection is the retention of some or the entire tooth. It is generally necessary to endodontically treat mandibular molars before bicuspidization6. Nevertheless, the disadvantage is that the remaining root or roots must undergo endodon- tic therapy and the crown must undergo restorative and prosthodontic management. In dentistry, endodontic care prior to bicuspidization procedure has a long history and it has remained today as a necessity in treating furcally in- volved mandibular molars. In case when the tooth has lost part of its root support, it will require a restoration to permit it to function independently or to serve as an abut- ment for a splint or crown or bridge. Unfortunately, a resto ration may lead to periodontal destruction, if the margins are defective or if non-occlusal surfaces do not have ana- tomic and physiologic form. This confirms the significance of accurate marginal adaptation of the final restoration7.

Farshchian and Kaiser stated that the success of bicuspidization depends on three factors: i stability of, and adequate bone support for, the individual tooth sections; ii absence of severe root fluting of the distal aspect of the mesial root or mesial aspect of the distal root; iii adequate separation of the mesial and distal roots, to enable the creation of an acceptable embrasure for effective oral hygiene. However, bicuspidization should be avoided when the furcation is deep and the roots are very close or fused together 2.

In this case, the roots of the involved tooth were adequate in length and periapically healthy, and therefore bicuspidization technique was preferred. Clinical periodontal scores and radiographies were recorded at 3, 6, 12 and 24 months after surgery, and the treatment procedure was found to be successful. Today, many of the practitioners prefer extracting the involved tooth and replacing it with fixed prostheses or dental implants to avoid the complexity of the treatment procedures 12. Although dental implants demonstrate a very high success rate, additional cost for the patient is still required. Therefore, tooth extraction must be the last treatment alternative with the recent developments in periodontics, endodontics and restorative dentistry.

CONCLUSION

Root amputation and root resection should be considered as another weapon in the arsenal of the dental surgeon, determined to retain and not remove the natural teeth. Although there are few case reports about bicuspidization in the literature, this technique is a successful alternative on such furcal defects which are nonrepairable with coronal approaches.With recent refinements in endodontics, periodontics and restorative dentistry, bicuspidization has received acceptance as a conservative and dependable dental treatment and teeth so treated have endured the demands of function.

REFERENCES