The free soft tissue autograft when used for increasing the amount of attached gingiva is a relatively simple surgical procedure.

 

Overlooking or failing to properly address a single one of these factors can result in incomplete coverage. The purpose of this paper is to outline those factors that must be considered when complete root coverage is attempted.

 

 

Recently the free soft tissue autograft'"3 as a one-step

surgical procedure, i.e., without coronally positioning a healed graft, has been shown to be the most predictable

procedure for achieving complete root coverage.4"6

 

 

 

Complete root coverage has been defined in clinical

terms (Fig. 1C and Fig. 7B) according to the following criteria:

The soft tissue margin must be at the cementoenamel junction.
 

There is clinical attachment to the root.
 

The sulcus depth is 2mm or less.
 

There is no bleeding on probing.

 

Using this criteria for success, Miller6 reported complete root coverage on 71 of 79 graft sites (89.9%). Holbrook and Ochsenbein,7 also using the free soft
tissue autograft as a one-step surgical procedure, reported complete root coverage on 22 of 50 graft sites (44%).

 

 

No procedure in periodontal surgery is more technically demanding or requires more attention to detail

than free soft tissue grafting for root coverage.

 

Many

factors are so interrelated that one cannot be singled

out as "the most important factor."

Ignoring or failing

to properly address a single factor can result in incomplete root coverage. The purpose of this paper is to

point out those factors which should be considered if

complete root coverage is attempted.

 

 

 

Factors Associated with Incomplete Coverage:

 

Improper Classification of Marginal Tissue Recession. Many areas of marginal tissue recession" fail to fall within Sullivan and Atkins'12 classification. An expanded classification13 is summarized in Table 2 and Figures 2 to 5. It includes recessions where only partial root coverage can be anticipated and those where root coverage is not anticipated.

Thus, the first step in predicting the degree of root coverage is to classify the recession.

 

Inadequate Root Planing. Cementum removal is a

controversial topic in periodontal therapy.14 Whether it is possible or necessary to remove all of the cementum

is not the question. Creating root anatomy conducive to root coverage should be the focus.

 

 

 

 

MILLER CLASSIFICATION OF MARGINAL TISSUE RECESSION & PREDICTABILITY OF ROOT COVERAGE

Miller,P.D.,Jr.:Aclassificationofmarginaltissuerecession. Int J Periodont Rest Dent 5: 9, 1985.

3 criteria must be considered

Marginal tissue recession’s relation to the muco-gingival junction

Periodontal status of the interdental area (soft tissue & bone)

Tooth mal-position

 

CLASS I

It´s the only class where the marginal recession does not reach the mucogingival junction.

There is no periodontal loss (bone or soft tissue) in the interdental area.

100% of root coverage can be anticipated.

 

CLASS II

The marginal recession extends to or beyond the mucogingival junction.

There is no periodontal loss (bone or soft tissue) in the interdental area.

100% of root coverage can be anticipated.

 

CLASS III

The marginal recession extends to or beyond the mucogingival junction.

There is periodontal loss in the interdental area (either from bone or soft tissue, or both) or tooth mal-position.

Only partial root coverage can be anticipated.

 

CLASS IV

The marginal recession extends to or beyond the mucogingival junction.

There is severe periodontal loss in the interdental area (either from bone or soft tissue, or both) and/or severe tooth mal-position.

Root coverage can not be anticipated.

 

 

I

The only where recession does not extend to the mucogingival junction.

 

I & II

No periodontal loss (bone or soft tissue) in the interdental area.

100% of root coverage can be anticipated.

 

III

Only partial root coverage can be anticipated.

 

IV

Root coverage can not be anticipated.

 

 

 

Failure to Treat the Planed Root with Citric Acid.

Conditioning the roots with citric acid 15"19 remains

controversial in periodontal therapy. Some investigators have shown surface changes histologically after conditioning with citric acid.These include widening of the dentinal tubules,1621 formation of "cementai pins,"16-20 removal of the "smear layer,"21 accelerated healing with accelerated reattachment16 (Fig. 6C), inhibition of epithelial migration,22 and the formation of a connective tissue attachment.23"25,28 Other

investigators17"19 have not been able to produce these histologic changes—hence the controversy. One cannot

ignore the fact, however, that complete root coverage on 88% of recessions treated with citric acid has been

obtained in one study6 while another study7 using meticulous surgical technique, showed complete root coverage on only 44% of recessions grafted without the use of citric acid.

 

Connective tissue attachment in humans on teeth treated with citric acid has been demonstrated.23"2

 

It is most important to complete citric acid conditioning before preparing the recipient site (Fig. 6A) since citric acid causes coagulation of blood. Coagulation compromises the blood flow to the recipient site and may ultimately cause loss of the graft.

 

Although connective tissue attachment has not been demonstrated in humans following free soft tissue grafting, it has been demonstrated with laterally positioned pedicle grafts following citric acid conditioning.28

 

 

Improper Preparation of the Recipient Site. The location of initial incisions is critical not only for placement of the graft but also for suturing.

The horizontal incision must be made at the level of the cementoenamel junction (Figs. IB and 8B).

If this incision is made apical to the cementoenamel junction, complete root coverage should not be attempted.

If, on the other hand, the horizontal incision is made coronal to the cemen- toenamel junction, the graft will be placed over enamel and a "dead space" will be created apical to the cemen- toenamel junction where the graft will not be in inti- mate contact with the root. That portion of the graft associated with the "dead space" is thus more likely to

slough.

 

Care should be taken to create a butt-joint margin in

the papilla with a horizontal incision rather than with a beveled margin (Figs. IB and 8B). A beveled margin in the papilla does not provide a clearly demarcated margin for graft placement, and there is a tendency to coronally displace the graft in suturing creating the "dead space."

Additionally, the butt-joint margin may ultimately provide enhanced circulation to the coronal aspect of the graft.

 

The vertical incisions are equally critical.

These vertical incisions should be made at the line angles of the

adjacent teeth to provide a complete interdental papilla for suturing (Figs. IB and 8B). If the vertical incisions

are not made at the line angles, that percentage of the total graft over the avascular root is increased.

 

 

The apical extent of the recipient site is equally important. The recipient site should be prepared a minimum of 3mm apical to the recession, i.e., both visible recession and "hidden" recession31 (pocket depth) (Fig. 8B). In multiple recessions or when the interdental papillae are small (Fig. 6A), the ratio of vascular to avascular surface can be increased by ex- tending the graft more apically (Fig. 6B).

 

 

 

Inadequate Size ofInterdental Papillae. The broader and thicker the interdental papilla (Fig. 8B), the greater the blood supply to the coronal aspect of the graft and

the easier the suturing. Conversely, thin, narrow pa- pillae (Fig. 6A) offer less blood supply and make sutur- ing difficult.

 

 

Improperly Prepared Donor Tissue.

 

 

Inadequate Graft Size. The size of the graft is deter- mined by the size of the recipient site. An accurate assessment can be made by making a pattern with adhesive foil®* at the recipient site prior to making actual incisions. In areas of multiple recessions or on prominent roots (such as on canines), it is best to take additional length (mesiodistally), for in suturing for root adaptation, more length may be required than initially anticipated. It is thus better to have too much length rather than too little.

 

Inadequate Graft Thickness. Grafting for root cov- erage requires a thicker graft than for simply gaining attached gingiva. In placing a graft over an avascular root, the entire thickness of the donor connective tissue should be taken where possible. The greater the thick- ness of the connective tissue the more intact is its

capillary system. Perhaps this capillary system will al- lowforimmediatecirculationwithinthegraftandthe

graft would not be solely dependent on the "plasmic" circulation described by Sullivan and Atkins.12

An adequate graft thickness is best obtained by leav- ing a very thin layer of submucosa on the underside of the graft where possible.

 

DehydrationofGraft.Sincetherecipientsiteiscom- pletely prepared prior to the removal of the donor tissue, it is not necessary to leave the graft out of the mouth for over a minute or two.

 

 

Inadequate Adaptation ofGraft to Root and Remain- ing Periosteal Bed. The importance of the intimate contact of the graft to the root and periosteal bed has been emphasized earlier.

Another recommended individual sutures into each papilla to approximate the butt-joint margins of the graft and the papillae.6 The latter enhanced intimate contact of the graft with the

periosteal bed by two apical sutures into the periosteum that were angled distally rather than apically (Fig. 6B). This type of suturing also minimizes shrinkage and may keep the vascular channels patent within the graft.

The placement of a periodontal dressing in the vestibule further promotes intimate contact of *he graft with the

periosteal bed at the apical aspect of the graft.

 

 

ExcessorProlongedPressureinCoaptationofSu-

tured Graft. Sullivan and Atkins12 advocated pressure

coaptation to the graft after suturing to prevent the formation of a hematoma under the graft. Probably, the formation of a hematoma is not a clinical concern, and the pressure applied in coaptation may compro- mise the necessary blood flow to the graft. A moderately bleeding surface (Fig. 8B) may actually enhance circu- lation.

 

 

 

Failure to Stabilize the Graft. Adequate suturing is of primary importance in graft stabilization. The graft must remain in intimate contact with the root when the lip is manipulated or stretched.

 

Reduction ofInflammation Prior to Grafting. It is a standard procedure to reduce inflammation and to maximize soft tissue healing and shrinkage by initial preparation prior to embarking on periodontal surgery. This is not suggested in free soft tissue grafting for root coverage since it actually may have a negative influence. A pathologically involved papilla offers a larger papilla for suturing to and bleeds more profusely when cut. This bleeding may actually enhance circulation to the coronal margin of the graft if the graft margin is inti- mately approximated to the "butt-joint" margin in the papilla. Of viously, root planing of the entire area, not just the root surface to be grafted should be completed at the surgical appointment before any incisions are made.

 

Trauma , o Graft during Initial Healing.

 

A review of the patients' health questionnaires revealed 100% correlation be- tween failure to obtain root coverage and heavy smok- ing.

Further investigation revealed that "light" or "occasional" smokers (five cigarettes or less per day) responded as favorably as nonsmokers.

 

After this correlation was made, heavy smokers were requested to refrain from smoking during the initial healingphase(2weeks).Inthosewhodidrefrain,the level of root coverage was comparable to that of non- smokers.

 

 

The free soft tissue autografi for root coverage is a more stressful

procedure for the periodontist than the commonly per- formed free soft tissue autografi where root coverage is not attempted. Not only is each step more critical but also the periodontist has been "taught" for over 20 years that roots cannot be covered with a free gingival graft, and if they are covered, a pocket is created. This tends to undermine confidence resulting in a tentative effort that usually fails.