Root Resective Procedures

Rationale

The aim is to remove unbeatable root parts in otherwise retainable and restorable multirooted teeth. It is imperative to assess beforehand the impact the treatment will have on the periodontal and occlusal status, integrating these data into the necessary restorative procedures.

Introduction

The first step is to finish the root canal treatment in the retainable roots and obturation of the pulp chamber and crown access. The need to reflect a flap is determined on a case-by-case basis; it is dependent on furca anatomy, location, degree of caries, fracture depth, and amount of access needed39.

The real-time vision provided by the microscope is replacing the use of multiple radiographs.

Indications

The following are conditions that are good indications for surgery:

• grade III furcation defect
• severe pocket depth involving only one of the roots
• extensive root caries, creating a non-restorable condition
• irreparable perforation or resorption in one of the roots
• VRF in one of the roots
• one root not amenable to conventional or surgical endodontic treatment and intentional replantation not possible.

Contraindications

The following are conditions that are not good indications for surgery:

• extensive bone loss of all roots
• pronounced tooth mobility
• too far extending apical furca (access would leave little bone support and difficult to clean infrabony defect)
• fused or "C-shaped" roots
• no roots amenable to conventional or surgical endodontics
• a crown/root ratio of the retained root that offers insufficient bone support.

Root Amputation

Amputation removes only the root. It is normally used in maxillary molars where trifurcations exist. The advantages of this are that it retains the crown and the contact point, the alveolus is easily covered by the palatally rotated flap (easier when the distobuccal root is removed), and no restorative procedure is necessary (Fig7-31). However, the procedure is not easy, and hygiene is difficult to maintain.

Hemisectioning

Hemisectioning removes the root and its corresponding crown. It is normally used in mandibular molars where bifurcation exists. The procedure is relatively easy, and hygiene is straightforward. However, it is more difficult to cover the alveolus and restorative procedures are necessary.

Assessment and Planning

Evaluation of the status of the periodontium is necessary prior to planning root removal, not only to determine periodontal health, but also to assist in planning the actual surgical procedure. It is essential to avoid the creation of a localized periodontal defect which would be difficult to manage after resectioning; the ideal situation is when furcas are above the mesial and distal crestal bone level.

Likewise, the restorative needs of the tooth in question must be assessed and integrated into the anticipated surgical procedure to ensure the positioning of tooth margins is in good relationship to the osseous crest, and to manage the anticipated changes in occlusal relationships and masticatory forces. It is accepted that a uniform bone crest height should equal three-quarters of the distance between the dentin-enamel junction and the apex of the root40.

Invaginating root concavities

Invaginating root concavities are common in mesiobuccal roots of maxillary molars. In addition, the furcal aspects of the buccal roots almost always diverge palatally. In mandibular molar roots, concavities are found 100% of the time in mesial roots and 99% of the time in distal roots.

Furcation size, shape, and spatial position

Narrow furcation and root proximity can result in damage to the retained root or failure to remove the root flush with the tooth cervix. A gouged root structure or residual root spurs will often enhance localized periodontal breakdown and case failure.

Also, the furcation position relative to the cervix of the tooth will vary, with the mesial furcation on maxillary molars more apically placed than the buccal furcation, and the distal furcation is often closer to the cervical line than the buccal furcation. In mandibular roots the lingual furcation is often more apically placed than the buccal.

The further we move distally, the more the tendency to root fusion, making root resectioning more difficult. Moreover, fusion of buccal roots to palatal is difficult to determine in maxillary molars, whereas close proximity and possible fusion on mandibular teeth is more obvious except for С-shaped root canals. The patient must be informed that extraction will be necessary if the anatomy of the remaining tooth does not fit into the desired periodontal result.