Introduction to osseous resective surgeries
The aim of surgical periodontal pocket therapy is to eliminate or reduce the periodontal pocket depth, achieving a healthy periodontium and creating a periodontal tissue architecture that facilitates the self-performed oral hygiene measures by the patient. The ideal method to treat periodontal pocket and periodontal bony defects is the regeneration of lost bone, periodontal ligament, and cementum resulting in a new coronal position of the connective tissue and junctional epithelial attachments. Another method is to remove the walls of the bony defect and removal of the associated pocket wall, thereby recontouring the bone and placing the gingiva in a more apical position.
In periodontitis, the bone defects that are formed due to bone loss, create an environment which favors the re-formation of pocket. So, it becomes important to reshape the bone, which minimizes the chances of re-formation of the periodontal pocket. The name “osseous resective surgery” itself indicates the removal of bone in such a way that a physiological bone contour (explained later) is achieved. This procedure involves the removal of tooth-supporting bone (ostectomy) and tooth non-supporting bone (osteoplasty).
The concept of osseous resective surgery was put forward by Schluger 1 in 1949 and subsequently by Ochsenbein 2 in 1958 and Prichard 3 in 1961. In 1952 Schluger explained in detail the need for re-contouring the periodontal bone. He explained that the periodontal inflammation causes bone loss which alters the outline of the bony crest. The gingiva overlying the bone retains the attachment “memory”, aroused by bone and bony spicules left in situ. In other words, it can be said that ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……..
Before going into details about the basic steps involved in osseous resective surgery, let us first discuss the normal physiology of alveolar bone and terminologies used in this topic.
Normal physiology of alveolar bone
The inflammatory periodontal diseases are always associated with repair, both in soft tissue and hard tissue. In case of hard tissue or alveolar bone, if the inflammatory destruction overrides the reparative process, loss of bone and bony defects result. Whereas, in case of the reparative process overriding the destructive process, bone deposition takes place in such a way that it is able to provide support to the involved tooth. To understand the bony architecture in pathological conditions, let us first discuss the normal alveolar bone physiology,
Normally, the interproximal bone is more coronal in position than the labial or lingual/palatal bone and is pyramidal in shape. This architecture is more prominent in the anterior maxillary and mandibular areas. In the posterior maxillary and mandibular teeth, the interdental bone level is closer to the labial or lingual/palatal bone margins. Also, the interproximal bone is more in both mesiodistal and labiolingual/labiopalatal dimensions. This situation is most suitable for crater formation.
The bony margins around teeth usually ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……..
There are some basic terminologies, one should be familiar with, before we go ahead with our main discussion.
In suprabony pockets, the base of the pocket is above the alveolar crest.
Here, the base of the pocket is below the alveolar crest.
One wall, two wall, and three wall defects:
Intrabony defects are classified as one wall, two wall and three wall defects, depending on remaining walls around the defect (see “Patterns of bone destruction in periodontal diseases”).
Periodontal surgery involving modification of the bony support of the teeth.
A term with an appropriate modifier, commonly used in periodontics to describe gingival and/or bony form 4.
A concept of soft tissue or bony form that includes positive architecture in vertical dimension, buccal-lingual contours, devoid of ledges, exostoses and interradicular grooves 4.
When the crest of the interdental gingiva or bone is located coronal to its midfacial/midlingual margins 4.
Interdental bone and radicular bone are at the same level.
When the crest of the interdental gingiva or bone is located apical to it’s midfacial and mid-lingual margins 4.
A saucer-shaped defect of soft tissue or bone, often seen interdentally 4.
A benign bony growth, projecting outward from the surface of the bone.
Objectives of osseous resective surgery
The primary objective of the resective surgery is to remove osseous deformities and create a physiological contour of the gingiva. Following are the objectives of osseous resective surgery:
- Elimination of periodontal pockets and the creation of shallow gingival sulcus that can be readily maintained by the patient.
- To create a periodontal tissue contour that permits to accomplish effective plaque control.
- To create a gingival contour that closely matches the contour of gingiva after healing.
- To permit primary closure of the flap margins.
- To create additional crown length for proper construction of restorations.
Indications and contraindications of osseous resective surgery
- In cases with flat or reverse bony architecture,
- In cases with exostoses and ledges,
- In cases with shallow bony defects <3 mm,
- In grade I and shallow grade II furcation areas,
- For bony contouring in conjunction with root resection procedure, and
- In regenerative procedures to achieve primary flap closure.
- In areas with esthetic concerns (maxillary and mandibular anterior areas).
- In cases with isolated defects in which bone resection to achieve positive architecture will result in excessive bone loss around adjacent teeth.
- In cases with severe bone loss.
- In the patients with root hypersensitivity, osseous resection will result in more root exposure causing increased hypersensitivity.
- Anatomical factors limiting osseous resective procedures,
- In close proximity to the maxillary sinus.
- In cases wit shallow palate, osseous resection may result in negative architecture.
- In ascending mandibular ramus, the recontouring of the basal mandibular bone should not be done and apical positioning of the flap cannot be achieved.
- The external oblique ridge of the mandible presents the same problem. The contouring of the basal bone should not be done and apical positioning of the flap is difficult. Also, it will further reduce the vestibular depth.
Classification of osseous surgeries
Osseous surgery may be,
This involves regeneration or substitution of bone.
This involves resection or removal of bone. It can be further divided into two types,
It involves the establishment of positive or normal physiological architecture of bone.
It involves removal of extensive bone, which leads to a reduction in bone support to the tooth and hence long-term prognosis of the tooth.
Concept of osteoplasty and ostectomy
As the name indicates, osseous resective surgery involves removal of bone with the aim of achieving a physiological bone architecture. There are two terms used to explain the bone removal around teeth: osteoplasty and ostectomy.
It is the reshaping of the alveolar process to achieve a more physiological form without removal of supporting bone 5. It is applied to treat buccal and lingual bony ledges or tori, shallow lingual or buccal ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……..
It is the excision of bone or a portion of the bone. In periodontics, ostectomy is done to correct or reduce deformities caused by periodontitis in the marginal and intra-alveolar bone and includes the removal of supporting bone 5. It is done to treat shallow (1-2 mm deep) to medium (3-4 mm deep) intrabony and hemiseptal osseous defects and to correct reversals in the osseous topography 8, 9. The endpoint of ostectomy procedure done in conjunction with an apically positioned flap or a thinned palatal flap, is the elimination of an intrabony pocket 10.
Before making a surgical entry, bone sounding is done to evaluate the bone topography. The buccal and lingual plates may have different thickness and variable topography due to the reparative process going on in the inflamed periodontal tissue. Bone sounding gives us a vague idea about the topography of the underlying bone. Even very skilled clinicians cannot identify the exact topography of underlying bone through bone sounding (especially in cases where multiple vertical bone defects are present). But when combined with other diagnostic aids like radiographs, we can get a lot of information about bony topography before making the actual surgical entry.
Technique of bone sounding:
The technique of bone sounding involves insertion of a periodontal probe in profoundly anesthetized gingiva until the tip of the probe contacts the bone. The probe is penetrated horizontally and vertically through the gingiva down to the bone in order to assess the bone morphology. Greenberg et al. (1976) 11 referred to this technique as transgingival probing and reported that the vertically probed bone level and the surgically confirmed bone level were closely correlated. Bone sounding may accurately assess the extent of the buccal or lingual/palatal bone defects. In the case of vertical defects, bone sounding may provide insight into the topography of the remaining walls, which many times is not possible with radiographs due to overlapping of the buccal and lingual/ palatal plates.
Bone sounding also improves the accuracy of furcation diagnosis. In mandibular molars, the radiolucency in the furcation areas on radiographs is ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……..
Treatment planning for osseous resective surgery
The local examination, radiographic examination, periodontal probing and transgingival probing are used to make a proper treatment plan for osseous resective surgery. Soft tissue palpation provides information regarding any bony protuberances, tori, etc. The radiographic examination provides information regarding the type of bone loss as well as the severity of bone loss. Since radiographs provide a two-dimensional image of a three-dimensional object, exact bony architecture cannot be determined, but when combined with other examinations such as transgingival probing; a lot of information can be obtained. Most accurate information regarding the bony architecture can be obtained by computed tomographic (CT) scan. Cone beam computed tomography provides a very clear picture of a tooth and its surrounding bone.
Careful periodontal probing provides important information regarding pocket depth, location of the base of the pocket relative to the mucogingival junction, number of the bony wall remaining and furcation involvement. Trans-gingival probing, as already explained, provides important information regarding three-dimensional bony architecture.
Factors influencing treatment planning for osseous resective surgery
Osseous resective surgery should be planned carefully because any injudicious removal of bone may result in irreversible damage to the periodontal tissues. When planning for an osseous resective surgery, many factors are considered which determine the amount of bone resection. Following is the detailed explanation of these factors,
Type of bone defect:
The planning for osseous resective surgery mainly depends on the type of bone defect, its depth and configuration and morphology and anatomic position of adjacent teeth. Depending on all these factors, the amount of bone resection is determined. Most commonly found osseous defects in posterior teeth are interdental craters 12-14.
Root form and root trunk morphology:
Root form and root trunk morphology in the case of posterior teeth has a major influence in the determination of the amount of osseous resection. Root trunk is the measured distance between CEJ and furcation entrance. More the ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……..
Furcation involvement has a great influence on the treatment planning for osseous resective surgery. Bone loss in the furcation area of the maxillary and mandibular posterior teeth is commonly found in inflammatory periodontal diseases. As already stated, the root trunk length and morphology are major factors determining the furcation involvement. Treatment of teeth with furcation involvement has been discussed in “Furcation involvement and its management”.
Inclination of the teeth:
As all the teeth in both maxillary and mandibular dental arch are inclined at different angulation both mesiodistally and buccolingually, the bony architecture around these teeth is variable. The position of the CEJ may also vary buccally and lingually, as in the case of mandibular molar, where due to crown inclination the CEJ on lingual aspect is placed more apically than buccal aspect. The facial alveolar bone thickness is less in teeth closer to midline which increases distally. The inflammatory bone loss in anterior areas cause dehiscence later on resulting in recession.
In irregularly placed teeth, the bone defects also vary according to the presence of the amount of bone. In cases where the interdental septum is thin the inflammation causes loss of complete septa and in cases with thick interdental bone mesiodistally and buccolingually the inflammation usually causes a crater-like bone defect.
Alveolar marginal bone architecture:
The shape and form of the bony margin are very important factors while doing the osseous resection. The bony alterations may vary from thickened bony ledges and exostoses to dehiscence and fenestration. The marginal bone may have a flat or reverse architecture. Reverse architecture is commonly associated with the interdental crater formation. It has been shown that maxilla has more thickened bony margins as compared to the mandible and marginal defects are more frequently found in maxillary posterior teeth 13.
After doing a thorough pre-surgical examination, the surgical entry into the involved area is planned. The patient is explained in detail about the procedure including the expected outcome of the treatment as well as the complications that may occur during and after the procedure. After achieving a sound local anesthesia, the periodontal flap is reflected to get complete ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……..
The osseous resection is initiated after the bone margins and bony defect are clearly visible. The bone reshaping can be done by hand or rotary instruments. If the rotary instruments are used, use of water coolant is critical. Overheating of bone may cause bone necrosis, which is not desirable. In areas with thick bone such as tori and heavier ledges, rotary instruments are used routinely. It must be remembered that while reshaping the bone in root proximity, any nicking or scratching of root surface should be avoided, which may cause root sensitivity and other post-operative complications. When close to the root surface, hand instruments are more suitable.
In other words, we can say that while reducing heavy bone mass, rotary instruments are suitable and while reshaping thin bone in close proximity to the root surface, hand instruments are more suitable. Making horizontal and vertical grooves, to desired depth while performing osseous resection is a very preferable method to ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ………
Large diameter burs are more suitable in this procedure because small diameter burs usually produce pits in the bone which are difficult to reshape. Secondly, small burs may invade the nutrient canals in the bone which does not usually happen with large diameter burs.
In areas with thin bone, the use of hand-instruments is recommended because with them there are fewer chances of root damage. Thin chisels and rasps are very effective in reshaping and leveling the craters and carving the thin bony margins. Many clinicians use a chisel and mallet while finishing the bone reshaping procedure because it is more controlled as compared to rotary instruments.
The surgical procedure to eliminate the bony defect involves the following steps,
In health, the alveolar bone and gingiva covering the roots of teeth have a relative prominence over the interradicular counterpart, especially in the anterior dentition. This creates a self-maintainable architecture of periodontal tissue. Another point to be remembered is that the prime objective of periodontal surgery is to replace a pocket with the selective recession which is maintainable.
Interradicular grooving is a procedure where grooves are made in the interradicular areas till the desired depth and later on these are merged with the ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……..
Interradicular grooving is contraindicated in the inter-proximal bone between most of the upper first and second molars because of sharp distal flare of the distobuccal root of the first molar. If the procedure is attempted in these areas, exposure of the root commonly results, which may complicate the procedure.
This is the second step of surgical procedure which involves gradualization of the bone on the entire root surface, thus creating a smooth, blended surface for good flap adaptation. In areas with thick bony ledges this procedure results in a smooth blended bone surface, whereas in areas with thin bone, where vertical grooving is very minor or the radicular bone is thin or fenestrated; this step is not necessary.
It must be remembered that both interradicular grooving and radicular blending are purely osteoplastic procedures which do not remove supporting bone. In most cases, the shallow craters, thick osseous ledges and class I and early class II furcation involvements are treated almost entirely with these two steps.
Flattening the interproximal bone:
This step involves the removal of a small amount of supporting bone to create a leveled interproximal bone. This step is indicated where interproximal bone levels vary horizontally. This step is particularly indicated in hemiseptal defects. This step is not indicated in classical interdental crater defects and in flat interproximal defects. This step is commonly done in coronally placed one wall ledge over the three-wall angular defect. A properly finished procedure results in a well-contoured ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……..
Gradualizing marginal bone:
Heavy ledges of the marginal bone is a common finding, especially in the molar region of the lower arch. Reshaping the marginal bone to achieve a sound, regular base for gingival tissue adaptation is necessary for completing the procedure. While performing bone reshaping, small projections of bone may be left at gingival line angles commonly referred to as widow’s peaks. If left behind, these small insignificant bony spicules are resorbed but not before the healing epithelial attachment has regenerated and has become coronal to them. Thus, these act as curtain rods holding the gingiva in a craterlike pattern after the crater has been leveled. Finally, it results in failure to achieve pocket elimination.
Use of hand instruments over rotary instruments is highly recommended in this step, if the bone is thin. The final outcome of the procedure is a levelled bone, which is nicely contoured around the teeth, following root morphology and facilitating close flap adaptation. A common error committed during gradualizing marginal bone is ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……..
Another error is over-contouring. Over contoured bony margins are not desirable as they may not be well maintained by the overlying gingiva. This results in several thick rolled festoons which are extremely persistent. The bone should be contoured according to the natural contour of the gingiva.
For the osseous resective procedure, we need to have full access to the bone. Inadequate flap reflection (mouseholding) does more harm than adequately reflected flap. So, such conservative approach should be avoided because it may lead to some serious errors. Thus, one must have an adequate room for observation and performing the surgical procedure. Also, the steps in osseous resection should be finished as fast as possible because over manipulation of the bone and longer duration of the surgery is associated with post-operative swelling.
Correction of various bony defects
Correction of interproximal craters:
Interproximal crates are the most common periodontal bone defects. The management of shallow craters is a relatively simple procedure. The procedure involves reducing the buccal and lingual walls so that the base of the original depression becomes a leveled floor in the interproximal area. Complications arise when the defect is deep. The thickness of buccal and lingual plates may also vary. If one wall is thin and the other is thick, the interproximal floor may be sloped towards the thin wall by leveling the thin bony plate and merely sloping the thick bony plate. If the defect is deep and it is anticipated that leveling of the interproximal bone may cause unwanted loss of tooth-supporting bone, regenerative procedures may be attempted.
Another error in the correction of interproximal bone is the therapeutic invasion of the furcation. We have to consider the position of the furcation area while leveling the interproximal bone because furcation involvement compromises the long-term prognosis of the tooth. Because of the same reason various procedures like ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……..
Correction of intrabony or hemiseptal defects:
Hemiseptal defects are common defects of proximal bone. The name ‘hemiseptal’ indicates the resorptive pattern which destroys a portion of the septum adjacent to one root, but not the portion next to adjacent root. According to Carnevale and Kaldahl (2000) 17, only ≤ 3 mm intrabony or hemiseptal defects are suitable for osseous resective surgery procedures because most of the clinical reports and experimental trials on ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……..
Correction of reversed osseous topography:
Reversed osseous topography (facial or lingual radicular osseous surface in a more coronal position than the interproximal surface), results from periodontitis or ostectomy performed to eliminate the osseous walls of an intrabony or hemiseptal interproximal defect. It can be corrected by removing facial and/or lingual bone so that the radicular bone level becomes apical to the interproximal bone level. As already stated, the most appropriate way to assess the bone contour is to follow the CEJ line of adjacent teeth.
Flap management after osseous resective surgery
Irrespective of whether osseous resection has been done or not, the flap tissue should be adapted over the alveolar process and towards teeth before completion of the surgery, to assess any further reshaping or recontouring of the flap. To achieve the optimal gingival contour after healing, thinning of the flap may be indicated. A BP #12B blade or fine surgical scissors may be used to reshape the flap. Thinning of the flap should be done carefully because if it is made too thin, it may necrotize and leave exposed bone behind. Also, care should be taken not to cause any excessive trauma to the flap during recontouring, which may also cause necrosis of the tissue and prolonged healing.
Older practice advocated by many authors was to leave the alveolar crest exposed to achieve pocket elimination. However, presently it is recommended to completely cover the alveolar process with thin flap margins. Exaggerated interproximal incisions may be given to include maximum interdental ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……..
In areas of esthetic concerns, such as maxillary anterior sextant, the osseous resection may cause recession. The papilla preservation technique in association with a thinned palatal flap can be used in such cases. If the bone defects are confined to the palatal aspect, a palatal approach without the use of a buccal flap can be utilized. In treating “gummy smile”, the general principles of the soft tissue management in osseous resective surgery are conversely applied.
Wound healing following osseous resective surgery
Wound healing events after osseous resective surgery are similar to that described for flap surgery. It depends on variables like tissue management during incision, flap thinning, flap management, the configuration of the defects and amount of trauma to which periodontium is exposed during surgery. It has been shown that healing following flap elevation with or without osseous resection is associated with crestal bone resorption ranging from 0 mm to 0.8 mm 22.
The best histological evidence of healing after osseous resective surgery comes from Wilderman et al. (1970) 23, who studied 23 block sections of teeth on which osteoplasty combined with mucoperiosteal flap was done. Crestal bone loss at interdental, radicular and furcation sites was 0.23 mm, 0.55 mm and 0.88 mm at six months post-surgery. They reported that superficial bone necrosis with intense osteoclastic activity was a common finding. In the case of thin bone, the resorption was seen on the periodontal ligament side, whereas in the case of thick bone the osteoclastic activity was primarily within the marrow spaces towards the periosteal side. The osteoblastic activity reached its peak at 21 days and after six months a little bone remodeling was seen.
The source of cells for the early ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……..
The osseous resective surgeries are important component of surgical periodontal therapy. The main objective of this therapy is to achieve periodontal soft and hard tissue architecture, which is most conducive for self-oral hygiene maintenance by the patient. The above discussion was focused on various aspects of osseous resection in periodontal bone defects. Another aspect of re-establishment of appropriate periodontal architecture is periodontal regenerative therapy. A detailed description of periodontal regeneration is available in the upcoming chapters.
References are available in the hard-copy of the website.