Close to the bone

23 August, 2011 / Infocus
 

The term resective bone surgery is applied to all procedures employed to eliminate crater and angular defects caused by the bone reabsorption typical of periodontal disease. Elimination of craters and osseous angular defects is therefore vital to obtaining an optimum gingival profile and maintaining shallow pockets after periodontal surgery.

Bone defects
Bone defects consist of localised reabsorption of the osseous alveolar crest around the tooth. They are also known as intraosseous defects as they are formed within the bone mass and are classified according to the number of constituent walls. Bone defects may occur in various sites around the same tooth and are usually located in the inter-proximal space. However, they may also occur in the buccal and/or palatal and lingual bone tissue. If they occur in the bone tissue of a root furcation, there may also be some degree of reabsorption between the roots, in the severest cases, establishing communication between the buccal and palatal or lingual sectors (Figs 1-4).

Resective bone surgery is not indicated for very large bone defects which are more effectively treated by regenerative or additive bone surgery (or a combination of both).

Osteoplasty
The term osteoplasty was introduced by Friedman in 1955. The aim of this technique is to reshape the bone to create a physiological form without removing the supporting bone (tissue connected to the tooth via periodontal fibres).

Surgical techniques
After elevating a full thickness flap, osteoplasty is performed using medium grain diamonds mounted on a turbine or micromotor. The operation site must be abundantly irrigated with sterile saline solution. Initially, the diamond is moved in a coronal-apical direction to reduce the thickness of the bone. The surface is then finished with the same diamond using a brush–type movement in a mesiodistal direction. During the operation, great care must be taken to avoid touching the root surfaces with the rotating diamond (Fig 5).

Bone reabsorption caused by periodontal disease has modified the bone architecture. After elevating a full thickness flap, it was decided to reshape the bone architecture by osteoplasty (Fig 6).

After osteoplasty, the bone margin is thinner and the ledge has been eliminated without removing the supporting bone (Fig 7).

Ostectomy
Ostectomy describes the surgical procedure employed to remove the supporting tissue (bone connected to the tooth by means of periodontal fibres). This technique is used to re-establish the physiological contour of bone tissue altered by periodontal disease.

Fig 8 – The physiological architecture of the bone has been completely altered by bone reabsorption caused by periodontal disease.

Fig 9 – Ostectomy has been performed. This operation has recreated the physiological architecture of the Alveolar bone. The inter-proximal bone is now more tapered and located more coronally to the radicular bone.

Conclusion
Resective bone surgery is by definition destructive and does not in itself cure periodontitis as it is an infectious disease. This type of surgery is performed exclusively in the case of minor alterations in the bone architecture which, in association with periodontal pockets, facilitate the progression of periodontal disease.


Case study

(see Figs 10-13)
A 55-year-old male patient suffering from chronic periodontitis. Premolar and molar periodontal pockets are present with an average pocket depth of 6 to 7 mm. The patient underwent hygiene phase therapy which reduced the pockets to 5 to 6 mm.

Maintenance
This new architecture facilitates bacterial plaque control and thus maintenance of a healthy periodontium.

The patient was included in a cycle of regular follow up appointments for professional prophylaxis.


About the author

Dr Alan Maxwell is a specialist in periodontics. He works at Care Dental Focus (Crieff), the Scottish Centre for Excellence in Dentistry (Glasgow) and Queen’s Cross Dental Practice (Aberdeen).

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