Bikuspidizasyon: olgu sunumu

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Introduction
The treatment, management and long-term retention of mandibular molar teeth exhibiting furcation
invasions (FI) have always been a challenge to the discerning general dentist or dental specialist. The treatment may involve combining restorative dentistry,
endodontics and periodontics so that the teeth are
retained in whole or in part. Such teeth can be useful as
independent units of mastication or as abutments in
simple fixed bridges. Continued periodontal breakdown may lead to total loss of tooth unless these defects
can be repaired or eliminated and health of the tissues
restored. Thus tooth separation and resection procedures are used to preserve as much tooth structure as
possible rather than sacrificing the whole tooth (1).
The term "tooth resection" denotes the excision and
removal of any segment of the tooth or a root with or
without its accompanying crown portion. Various
resection procedures described are: root amputation,
hemisection, radisection and bisection. Bisection or
bicuspidization is the separation of mesial and distal
roots of mandibular molars along with their coronal
portion, where both segments are then retained individually (2,3).
Several authors have listed the following indications
and contraindications for bicuspidization (4-8):
Periodontal indications
∗ Severe bone loss affecting one or more roots untreatable with regenerative procedures
∗ Class II or III furcation invasions or involvements
∗ Severe recession or dehiscence of a root
Endodontic or conservative indications
∗ Inability to successfully treat and fill a canal
*Department of Prosthetic Dentistry, Dental Sciences Center,
Gülhane Military Medical Academy
Reprint request: Mehmet Dalkýz, Department of Prosthetic Dentistry,
Dental Sciences Center, Gülhane Military Medical Academy, Etlik-
06018, Ankara, Turkey
E-mail: mdalkiz@yahoo.com
Date submitted: February 21, 2007
Date accepted: May 15, 2007
OLGU SUNUMU/CASE REPORT Gülhane Týp Dergisi 2008; 50: 42-45
© Gülhane Askeri Týp Akademisi 2008
Summary
The increased desire of patients to maintain their dentition
has forced conservative dentistry to conserve the teeth in
the mouth which are planned to be removed. In the light of
this finding it is known that periodontally compromised
teeth with severe bone loss at furcation area may well be
retained of their roots. In this case report bicuspidization of
the right first mandibular molar with a simple procedure
and subsequent prosthetic treatments are presented.
Key words: Bicuspidization, furcation defects, root separation
Özet
Bikuspidizasyon: olgu sunumu
Hastalarýn kendi diþlerinin saðlýklý bir þekilde korunmasýna
gösterdikleri özenin giderek artmasý sonucunda, koruyucu
diþ hekimliði çekimi düþünülen diþlerin aðýzda tutulmasý için
deðiþik tedavi alternatifleri aramaktadýr. Bu düþüncenin
ýþýðýnda, furkasyon bölgesinde aþýrý kemik kaybý olan diþlerin
çeþitli tedavi yöntemleri kullanýlarak aðýzda tutulduðu bilinmektedir. Bu makalede alt sað birinci molar diþin basit bir
yöntemle biküspidizasyonu ve sonrasýnda uygulanan protetik tedaviler sunulmaktadýr.
Anahtar kelimeler: Biküspidizasyon, furkasyon defektleri,
köklerin ayrýlmasýCilt 50 · Sayý 1 · Gülhane TD Bicuspidization · 43
∗ Root fracture or root perforation
∗ Root caries of the furcation area
Prosthetic indications
∗ Severe root proximity inadequate for a proper
embrasure space
∗ Root trunk fracture or decay with invasion of the
biological width
General contraindications to periodontal surgery
∗ Systemic factors
∗ Poor oral hygiene
Factors associated with local anatomy
∗ Fused roots
∗ Unfavorable tissue architecture
Endodontic factors
∗ Retained roots endodontically untreatable
∗ Excessive endodontic instrumentation of retained
roots
∗ Excessive deepening of pulp chamber floor
∗ Severe root resorption
Restorative factors
∗ Internal root decay
∗ Presence of a cemented post in the remaining root
Strategic considerations
∗ Consider adjacent teeth available for conventional
prosthetic restoration
∗ Consider removable prosthesis
∗ Consider implants
Advances in dentistry, as well as the increased desire
of patients to maintain their dentition, have lead to
treatment of teeth that once would have been separated.
In order to carry out this present day mandate, periodontally diseased teeth with severe bone loss at furcation area may well be retained by separation of their
roots. This article describes a simple procedure for
bicuspidization in mandibular molar and its subsequent
restoration.
Case Report
A 64-year-old female presented with the complaint
of pain of right mandibular first molar with a full metal
crown. On examination, the tooth was sensitive to percussion. On probing the area, there was a 7-mm-deep
periodontal pocket around the furcation area.
On radiographic examination, severe vertical bone
loss was evident at the furcation area. The bony support
of both roots was completely intact. But apical lesion
was investigated around each root. There was also an
apical lesion at the second premolar. After the removal
of full metal crown root canal treatments of both second premolar and first molar were finished (Figure 1).
The working canal length was determined and the
canals were biomechanically prepared using step back
technique. The canals were obturated with lateral condensation method and the chamber was filled with
glass-ionomer cement.
Under local anesthesia, the vertical cut method was
used to separate the crown. A long shank tapered fissure
carbide bur was used to make vertical cut toward the
bifurcation area. The distal part of the crown had a
severe loss of dentine, then a prefabricated post was
inserted and a core was built (Figure 2).
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.
The occlusal table was minimized to redirect the
forces along the long axis of each root. After healing of
the tissues, a fixed partial denture involving each root
and mandibular second premolar was given (Figures
3,4).
Discussion
Another approach to treating a Class III FI of a
mandibular molar is called "bisectioning." The clinician
splits the mandibular molar vertically through the furcation, without removing either half, leaving two separate roots that then are treated as bicuspids (a procedure
termed "bicuspidization"). Farshchian and Kaiser have
reported the success of a molar bisection with subseFigure 1. Vertical bone loss around the furcation area ýs shown
by the radiographs. The canals were obturated and the chamber
was filled. The tooth was separated. The fixed crown restorations
involving each root and mandibular second premolar were
cemented44 · Mart 2008 · Gülhane TD Dalkýz et al.
quent bicuspidization (9). They stated that the success
of bicuspidization depends on three factors:
1. Stability of, and adequate bone support for, the
individual tooth sections
2. Absence of severe root fluting of the distal aspect
of the mesial root or mesial aspect of the distal root
3. 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 (10). However, the disadvantage is
that the remaining root or roots must undergo
endodontic therapy and the crown must undergo
restorative management. The need for endodontic care
before root resectioning or sectioning (bisectioning) has
a long history in dentistry. It has remained today as a
necessity in treating mandibular molars before the partial removal of their roots or separation of their crowns
(11). However, failure to perform endodontic treatment
first is not a contraindication for root resectioning, if it
can be determined that a successful root canal filling is
practical and possible (12). It has been shown that vital
root resections are possible, especially in the maxilla,
with symptoms not being manifested until several
weeks after the placement of a sedative dressing of
choice (13).
Success of root resection and separation procedures
depends, to a large extent, on proper case selection. It is
Figure 3a. Buccal view of the prepared roots. b. Buccal view of
the final restoration. c. Occlusal view of the final restoration. d.
Full view of mandibular model. e. Occlusal view of both maxillary and mandibular models
Figure 4. Buccal views of separated right mandibular molar and
the final view of restorations
Figure 2. Furcation involvements and clinical procedures are
shown at the photographs. Vertical cut at the bifurcation area.
Distal part of the crown had a severe dentinal tissue loss. A prefabricated post was inserted and a core was built. A final view of
the metal ceramic restoration of separated molar and second premolarCilt 50 · Sayý 1 · Gülhane TD Bicuspidization · 45
important to consider the following factors before
deciding to undertake any of the root separation and
resection procedures.
∗ Advanced bone loss around furcation area acceptable level of bone around the remaining roots
∗ Angulations and position of the tooth in the arch.
A molar that is buccally, lingually, mesially or distally
titled, can not be separated and resected
∗ Divergence of the roots - teeth with divergent
roots is easier to resect. Closely approximated or fused
roots are poor candidates
∗ Length and curvature of roots - long and straight
roots are more favorable for root separation and resection than short, conical roots
∗ Feasibility of endodontics and restorative dentistry
in the root/roots to be retained
Root separation or resection has been used successfully to retain teeth with furcation involvement.
However, there are few disadvantages associated with it.
As with any surgical procedure, it can cause pain and
anxiety. Root surfaces that are reshaped by grinding in
the furcation or at the site of hemisection are more susceptible to caries. Often a favorable result may be negated by decay after treatment. Failure of endodontic
therapy due to any reason will cause failure of the procedure. In addition, 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 abutment for a
splint or bridge. Unfortunately, a restoration can contribute to periodontal destruction, if the margins are
defective or if non-occlusal surfaces do not have physiologic form. Also, an improperly shaped occlusal contact area may convert acceptable forces into destructive
forces and predispose the tooth to trauma from occlusion and ultimate failure of root separation and resection (14,15).
In the case reported, various aspects of occlusal
function such as location and size of contacts and the
steepness of cuspal inclines may have played a significant role in causing mobility before treatment. During
treatment, occlusal contacts were reduced in size and
repositioned more favorably. Lateral forces were
reduced by making cuspal inclines less steep and eliminating balancing incline contacts.
The prognosis for root separation or resection is the
same as for routine endodontic procedures provided
that case selection has been performed correctly and the
restoration is of an acceptable design relative to the
occlusal and periodontal needs of the patient. Root separation and resection should be considered as other
treatment options for the dental surgeons, determined
to retain and not remove the natural teeth. With recent
refinements in endodontics, periodontics and restorative dentistry, root separation and resection have
received acceptance as a conservative and dependable
dental treatment and teeth so treated have endured the
demands of function.