Due to the special anatomical conditions of the root bifurcation zone, scaling and scraping procedures are difficult to completely remove tartar and plaque from the root bifurcation zone and to provide long-term effective plaque control, so surgical treatment is often required. The ideal goal of surgical treatment is to establish a new attachment and complete healing of the root bifurcation lesion. However, this ideal result is not achieved in all cases due to the varying conditions. Therefore, the secondary goals of surgical treatment of root bifurcation lesions include removal of tartar and plaque from the root bifurcation site and the establishment of a good anatomical structure that facilitates self-plaque control and maintenance treatment. Different surgical methods should be used for different degrees of root bifurcation lesions. First, the choice of root bifurcation lesion treatment method Liang Zhaozhong of the special oral clinic of Urumqi Stomatological Hospital
If there is enamel protrusion in the root bifurcation area, or if the longitudinal groove in the root bifurcation area needs to be formed by osteoplasty to make the gingiva adhere better, root repositioning flap can also be used.
In the case of second-degree root bifurcation lesions of mandibular molars, bone grafting, guided tissue regeneration, or a combination of both may be considered in order to obtain new attachments. Deep second-degree root bifurcation lesions that are difficult to obtain new attachments can be considered for root repositioning flap surgery to eliminate periodontal pockets, expose the bifurcation area, and establish a good anatomical structure for self-plaque control. Some people also advocate the use of root bifurcation and tunneling, but it is easy to cause root sensitivity and root surface caries, and should be used with caution.
Grade III root bifurcation lesions are commonly treated by root amputation, hemicolectomy or root splitting, or tooth extraction.
Root repositioning flap, bone grafting, guided tissue regeneration, introduction of root amputation, hemicolectomy and root splitting.
Root amputation
Root amputation (or root resection) refers to the removal of one or two of the most severely damaged roots of a tooth with a bifurcation lesion to eliminate the lesion in the bifurcation area, while preserving the crown and the remaining roots to continue to function. It is commonly used in molar teeth with third or fourth degree root bifurcation lesions.
(I) Indications
1. The periodontal tissue of one or two roots (maxillary molars) of a multi-rooted tooth is severely damaged, and there is a third or fourth degree root bifurcation
The lesion of one or two roots of multiple teeth (maxillary molars) has serious periodontal tissue damage, and there is Ⅲ or Ⅳ degree root bifurcation, while the rest of the roots are less severe and the tooth loosening is not obvious.
2. One of the roots of the molar has a longitudinal fracture or transverse fracture, while the other roots are intact.
3. A root of the molar has a serious apical lesion, and the root canal is not accessible or the instrument is broken and cannot be removed, affecting the healing of the apical lesion.
4. A combined periodontal and endodontic lesion, one of which is obviously involved, can be treated with a complete root canal.
Preoperatively, the affected tooth should be treated with endodontic therapy and myring to reduce the myring burden of the tooth and also to reduce the buccolingual diameter of the crown. The patient must already have proper plaque control, otherwise the long-term outcome of the procedure is bound to be poor.
The following factors should also be considered when selecting the indication: ① Length and morphology of the root: If the lesion is mild and the root that can be preserved is too short or the root is curved, the root is not suitable for root amputation if it is not sufficient to support the function of the tooth after surgery. The length of the root column (the distance from the enamel bone boundary to the bifurcation): teeth with short root columns are suitable for root amputation and easy to operate; on the contrary, teeth with long root columns and bifurcation sites close to the apical area are not suitable for root amputation. ③ Angle of root bifurcation, with or without root fusion: large angle of root bifurcation is easy to treat and operate; small angle of bifurcation makes the operation more difficult, and if the root is partially fused, it is not suitable for root amputation. ④The amount of supporting tissue around the remaining root: if the amount of supporting tissue is small and not enough to support the tooth, it is not suitable for root amputation. ⑤ Tooth mobility: If the tooth mobility has
is more than II degree, then it is not suitable for root amputation treatment. (6) Whether oral cleaning appliances such as interdental brushes can enter the root bifurcation area after surgery: this will affect the maintenance of oral hygiene after surgery, if you cannot enter the root bifurcation area for cleaning and postoperative maintenance, then root amputation is not suitable. (7) The preserved affected root needs to be available for thorough root canal treatment.
(II) Surgical methods
1) Make an internal oblique incision and a vertical incision, turn the flap routinely, fully expose the bifurcation area, and thoroughly clean and level the root surface.
2. Root amputation. Use a sterilized turbine handpiece, install a fine crack drill (preferably diamond drill), cut off the affected root at the level of the bifurcation and remove it, pay attention to completely cut off the bifurcation, and avoid the residual stump-like root surface inverted concave. Trim the shape of the root surface so that a streamlined slope is formed from the bifurcation area to the crown contact area.
Root amputation
(1) The affected root is cut off with a high-speed fracture drill (2) After the affected root is cut off, the arrow shows the shape that should be trimmed (3) The section should be streamlined to eliminate the inverted concavity at the root bifurcation (4) The trimmed root surface resembles the shape of a fixed bridge to facilitate future oral hygiene.
(3) Filling of the root canal at the cross-sectional opening. Prepare a hole at the exposed root canal of the section and fill it with silver amalgam invert, taking care not to drop the silver mercury debris into the wound. In order to facilitate the surgery and shorten the time, the root canal opening of the root to be amputated can be slightly enlarged and deepened during the endodontic treatment and filled with silver amalgam from the pulpal cavity to eliminate the need for inverse filling during the root amputation process.
4. Scrape the deep part of the root bifurcation and the diseased tissue in the extraction socket, and if necessary, trim the irregular bone ridge shape. 5. After cleaning the wound, reset the gingival flap and suture it to cover the wound in the root amputation area as much as possible. Placement of the plugging agent.
If, in the course of flap surgery, a heavily involved root is temporarily found for root amputation, and root canal treatment cannot be performed in advance before surgery, root amputation can be performed first to remove the fractured root, and the remaining section can be filled with calcium hydroxide paste after direct pulp capping, and the pulp status can be reviewed regularly after surgery.
(C) Healing and care after root amputation Immediately after root amputation, the affected tooth will have more obvious loosening, patients should be advised to chew without the affected tooth as much as possible, and the affected tooth will gradually return to the preoperative stability after about 3 to 4 weeks. The healing process of the alveolar socket after root amputation is the same as the healing process of the extraction socket. The healing of the mucoperiosteal flap is the same as that of the flap procedure.
The most likely complication after root amputation is continued periodontal destruction of the remaining root or root fracture. The main reasons for root fracture are the reduction of the supporting role of the affected tooth, the change of the force direction, the original axial force into lateral force, which causes trauma to the affected tooth; or the preoperative failure to make a transfer; or the root canal wall is too thin during the root canal treatment, or the root canal has internal resorption resulting in root fracture due to root fragility.
Some studies have shown that teeth after root amputation can be retained for a long time and can function successfully with simple periodontal maintenance treatment. The key to long-term successful treatment is correct diagnosis, selection of indications, maintenance of good oral hygiene of the patient, and proper surgical operation and restoration.
III. Root separation
Root separation is only applicable to mandibular molar teeth. The mandibular molar with crown and root is cut off from the median along the buccolingual direction, so that it is separated into two halves, proximal and distal, forming two independent teeth like a single root. This can remove the deep lesion tissue in the root bifurcation area more thoroughly, eliminate the periodontal pocket there, and also eliminate the original root bifurcation lesion, which is conducive to plaque control and self-cleaning. The exposed dentin and bone part after being cut can be covered by a full crown restoration to reduce the possibility of caries.
(I) Indications
1. The lesion of degree III or IV in the root bifurcation area of the mandibular molar, and the local deep periodontal pocket cannot be eliminated.
2. There is sufficient supporting bone around the two roots of the affected teeth, and the teeth are not obviously loose.
(B) Surgical method
1. Root canal treatment is performed before surgery, and the pulp chamber is filled with silver amalgam.
2. An internal oblique incision is made to preserve as much gingival margin tissue as possible, especially at the root bifurcation, to facilitate the formation of the gingival papilla between the two “single-rooted teeth” after surgery. Vertical incisions can be made in the proximal and distal centers.
3. Turn over the full-thickness flap to fully expose the bifurcation area and scrape away the diseased tissue.
4. Using a diamond drill or a turbo fracture drill, cut along the buccolingual developmental sulcus of the affected tooth’s crown from the area directly opposite to the root bifurcation and divide it into two halves, proximal and distal. Two separate single-rooted teeth are formed and the shape of the proximal and distal mesial halves is trimmed.
5. Thorough debridement and scraping of the deep lesion tissue. Rinse, stop bleeding, reset the gingival flap and suture. Placement of periodontal plugging agents. It is advisable to make a temporary crown while the wound is healing to facilitate the formation of an interdental papilla and leave it for crown restoration after 6 to 8 weeks.
IV. Tooth hemicolectomy
Tooth hemisection, also known as hemisection, is to remove the root of a mandibular molar with more serious periodontal tissue damage together with the crown of the hemiside, while preserving the less diseased or normal hemiside to become a “single root tooth”, thus eliminating the root bifurcation lesion.
(A) Indications
1) A bifurcation lesion of a mandibular molar, one of which is involved and the other side is healthy, has supporting bone, is not loose, and can be treated with root canal therapy.
2. The affected tooth should be left as an abutment, especially when the affected tooth is the most distal tooth in the row, and half of the tooth can be used as the abutment of the restoration to avoid a single-end restoration.
(B) Surgical method
1. Preoperative root canal treatment and filling of the pulp chamber with silver amalgam.
2. Incision and flap are the same as root amputation. If the root bifurcation has been completely exposed, the flap may not be made.
3. The tooth is divided from the crown to the root bifurcation using a diamond drill or a turbo-cracking drill into two parts, proximal and distal, with the position of the cut slightly to the affected side in order to preserve more of the healthy side of the crown root.
Tooth hemicolectomy
(1) Molar root bifurcation lesion with severe destruction of periodontal tissue in one of the roots
(2)Tooth hemicolectomy
4) Extract the affected coronal roots, scrape the extraction sockets and the diseased tissues in the original root bifurcation area, and make bone trimming if necessary.
5. Trim the edge of the retained side of the section to form a good tooth shape.
6. Gingival flap restoration and suturing.
7.After complete healing of the wounded El, the restoration of the tooth or tooth row is carried out.