Treating Periodontal Defects

Nonsurgical periodontal treatment is often successful in treating most periodontal diseases but may leave isolated sites of deep pockets after treatment is complete. Dental professionals are faced with either accepting the remaining pockets and attempting to maintain them or referring the patient for periodontal surgery. Dental professionals may be reluctant to refer patients for surgical treatment because they assume it may extend far beyond the site of the isolated residual defect and may result in generalized post-operative recession, sensitivity, or unesthetic gingival contours.

OSSEOUS SURGERY

Traditional periodontal surgery routinely involves long incisions around multiple teeth. Osseous surgery is a frequently performed periodontal surgery and it is often done as a quadrant or sextant procedure. A guiding principle of osseous surgery is to apically position the gingival tissue so that the edge of the gingiva rests on the crest of the bone. This is done to open up the defect for oral hygiene procedures. In order to apicially position the flap, it is necessary to make an incision long enough to obtain a drape or flow of tissue from one tooth to the next. This frequently necessitates including several healthy teeth adjacent to periodontal defects.

While osseous surgery has an excellent track record for producing a stable and healthy periodontium as well as creating shallow pockets, it can also create post-surgical discomfort because of the long incisions, esthetically unattractive “long teeth” due to the necessity of apically positioning the gingiva, post-surgical sensitivity because of root exposure, and the inclusion of multiple healthy teeth in the surgical procedure in order to treat an isolated periodontal defect.

REGENERATIVE SURGERY

Regenerative periodontal surgery has increasingly replaced traditional osseous surgery as the standard surgical treatment for periodontal diseases. Regenerative surgery aims to regrow lost periodontal structures rather than remove and contour damaged bone in order to gain shallow pockets. Regenerative periodontal surgery may use bone grafts, guided tissue regeneration, growth factors, and often a combination of two or more of these materials. Results from regenerative surgery have continually improved both in predictably producing acceptable post-surgical pocket depths and in long-term maintenance of periodontal health. Unfortunately, gingival recession, exposed root surfaces, and post-operative sensitivity are still typical consequences of regenerative periodontal surgery. While these unwanted post-surgical outcomes are reduced with regenerative procedures when compared to osseous surgery, they remain a concern to the patient, the periodontist, and the dental hygienist.

MINIMALLY INVASIVE SURGERY (MIS)

Over the years, many attempts have been made to treat periodontal diseases using smaller incisions than those traditionally used for osseous surgery. These have taken many forms including replaced flap techniques, the excisional new attachment procedure (ENAP),¹ the Modified Widman procedure,² and Flap Curettage.³ Most of these procedures use small incisions to allow access for surgical cleaning. The theory is that if the root is thoroughly cleaned so that it is free of calculus, the gingiva will reattach to the root, making it possible to obtain regeneration of the attachment apparatus, ie, regrowth of bone, cementum, and periodontal ligament. While all of these procedures have demonstrated improvements in pocket depth and attachment levels over the presurgical levels, these procedures have also resulted in recession and residual pockets in deeper sites.

Minimally invasive periodontal surgery (MIS) is a surgical approach for the treatment of periodontal diseases that was introduced in 1995.^4-8 The guiding principle of minimally invasive surgery is to make the incisions as small as possible and to confine the periodontal surgical procedure to the site of the periodontal defect (Table 1). The MIS technique shares the basic concept of small incisions in common with previous small incision techniques such as the ENAP and Modified Widman Procedure. However, MIS also encompasses the concepts of regenerative procedures such as bone grafts and membrane therapy. This is in marked contrast to other small incision techniques.^4-8

With the MIS approach, if a defect is present between a molar and a bicuspid, the incision is confined only to that site and is not extended to the adjacent healthy areas. Additionally, the soft tissue at the incision site is maintained with no surgical thinning of the tissue as is routinely performed with osseous and regenerative surgery. This retention of tissue thickness is directly opposite to the ENAP procedure where the tissue surrounding the teeth is deliberately excised and thinned. With MIS, the retention of gingival tissue allows for the maintenance of papilla height at the surgical site and, in most instances, results in little or no post-surgical recession around either the teeth with periodontal defects or the adjacent healthy teeth.

In a prospective study of 160 sites with pre-operative pocket depths of 6 mm to 9 mm or greater treated with MIS, at 1 year all post-operative pockets were 4 mm or less (mean of 3.1 mm) with a mean of 0.05 mm of recession.⁸ This is a much more favorable result than reported with other periodontal regenerative surgical techniques.⁹ Clinically, these results indicate that the pockets were at an easily maintained level (4 mm or less) with no detectable post-operative recession. Many of these results have recently been independently confirmed in a European study.¹⁰

TECHNIQUE FOR MIS

The guiding principle of the MIS surgical approach is that the incisions are confined only to the site of the periodontal defects that have not responded to nonsurgical therapy. If the patient has responded well to root planing or other nonsurgical techniques but continues to have isolated sites with osseous defects or pockets deeper than 5 mm, MIS is confined only to the sites that have not adequately responded.

MIS is not performed as an area of treatment, such as a quadrant or sextant of surgery. The MIS incisions are made directly in the sulcus without removing any gingival tissue. No attempt is made to perform an inverse bevel incision or to surgically remove the ulcerated epithelium as is routine with traditional large and small incision surgical techniques. The soft tissue thickness is preserved to the greatest extent possible. This allows the gingival tissue to retain the regenerative material, such as bone grafts or enamel matrix protein, that is placed in the periodontal defect as well as allowing for the preservation of gingival esthetics.

Another major difference between MIS and traditional regenerative surgery is that the flaps are minimally reflected. With osseous and regenerative periodontal surgery techniques, the flap is reflected away from the underlying bone. This involves lifting or tearing the periosteum from the bone using periosteal elevators. The periosteum contains a significant portion of the blood supply to the gingiva. When the periosteum is damaged or destroyed during traditional periodontal surgery, the blood supply to the healing gingiva is reduced, which may contribute to post-surgical soft tissue damage such as loss of interproximal papilla and recession. In MIS, the gingiva is reflected only to the level of the bony walls of the defect using exclusively sharp dissection. By using sharp dissection, rather than a periosteal elevator, a clean surgical wound is created that heals faster and the periosteum remains intact so that the portion of the blood supply to the gingiva from the periosteum is retained.

Following sharp dissection of the gingiva, the granulation tissue in the defect is removed. Granulation tissue results from the body’s unsuccessful attempt to heal the periodontal defect and is heavily contaminated with bacteria. Granulation tissue must be removed in order to reduce the bacterial load in the periodontal defect as well as to create room for the placement of regenerative material.

Inadequate granulation tissue removal may be the cause of the poor results reported with nonsurgical regeneration procedures using closed root planing and enamel matrix protein (Emdogain^®*).¹¹ Following granulation tissue removal, the defect is visualized using high power surgical telescopes, endoscopes, or a surgical microscope. The roots are thoroughly cleaned using curets, the diamond safety tip** ultrasonic scaler, and finishing burs.

After the periodontal defect has been debrided, regenerative material is placed in the defect. The regenerative material most frequently used with MIS is a combination of freeze dried bone and enamel matrix protein (Emdogain). The specific material placed in the sites of MIS is changing rapidly with the advent of various tissue engineered materials. The flaps are sutured back to their original presurgical position and, in some instances, are placed at a more coronal position. Simple vertical mattress sutures are used to approximate the tissue and pressure is utilized for final positioning of the tissue. With the MIS surgical technique, a single suture is all that is necessary to close the surgical site.

Healing following MIS in most instances is more rapid than with traditional regenerative surgery due to the small incisions and reduced trauma to the underlying bone and periosteum. Patients usually need only over-the-counter pain medication and can return to most normal activity the day following surgery.

REFERENCES

1. Yukma R, Bowers G, Lawrence J, Fedi P. A clinical study of healing in humans following the excisional new attachment procedure. J Periodontol. 1976;47:696.
2. Ramfjord S, Caffesse R, Morrison E. Four modalities of periodontal treatment compared over 5 years. J Periodontol Res. 1987;22:222.
3. Lindhe J, Westfelt E, Nyman S, Socransky SS, Haffajee AD. Long-term effect of surgical/non-surgical treatment of periodontal disease. J Clin Periodontol. 1984;11:448.
4. Harrel SK, Rees TD. Granulation tissue removal in routine and minimally invasive surgical procedures. Compend Contin Educ Dent. 1995;16:960-967.
5. Harrel SK. A minimally invasive surgical approach for bone grafting. Int J Periodont Rest Dent. 1998;18:161-169.
6. Harrel SK. A minimally invasive surgical approach for periodontal regeneration: Surgical technique and observations. J Periodontol. 1999;70:1547-1557.
7. Harrel SK, Wright JM. Treatment of periodontal destruction associated with a cemental tear using minimally invasive surgery. J Periodontol. 2000;71:1761-1766.
8. Harrel SK, Wilson TG, Nunn ME. Prospective assessment of the use of enamel matrix proteins with minimally invasive surgery. J Periodontol. 2005;76:380-384.
9. Garrett S. Periodontal regeneration around natural teeth. Ann Periodontol. 1996;1:621-666.
10. Cortellini P, Tonetti MS. A minimally invasive surgical technique with an enamel matrix derivative in the regenerative treatment of intra-bony defects: a novel approach to limit morbidity. J Clin Periodontol. 2007;34:87-93.
11. Sculean A, Windisch P, Keglevich T, Gera I. Histologic evaluation of human intrabony defects following non-surgical periodontal therapy with and without application of an enamel matrix protein derivative. J Periodontol. 2003;74:153-160.

From Dimensions of Dental Hygiene. October 2007;5(10): 30, 32, 34.