564

Formation of Interdental Soft Tissue Defects After Surgical Treatment of Periodontitis William M.M.

This

Jenkins, * Phillip F. Wragg, * and

W.

Harper Gilmour1

study monitored the development and repair

of interdental soft tissue defects

following surgical treatment of Periodontitis in 21 patients. Open flap curettage was performed at 100 interdental areas with follow-up examinations 1, 3, and 6 months later. Interdental gingival contours were assessed both clinically and indirectly with silicone elastomer impressions from which stone models were obtained; defect depths were then calculated using the Reflex Microscope. Two types of defect were identified at the 1month follow-up: 13 interdental clefts (mean depth, 1.8 mm); and 30 craters, (mean depth, 1.6 mm). Although clefts tended to persist, craters showed a strong tendency to repair. Thus, at the 6-month follow-up, the mean depths of clefts and craters were 1.3 mm and 0.7 mm respectively. The development of soft tissue defects did not appear to be related to the use of a periodontal dressing nor did the existence of an underlying bone defect appear to be of etiological importance. Pre-operative probing depths, however, were positively associated with the occurrence of soft tissue craters (P 0.02). Pre-operatively, the overall mean probing depth and frequency of bleeding on probing were 5.3 mm and 100% respectively. At 6 months, these values were reduced to 2.0 =

clefts, craters, and interdental

with no soft tissue defect were compared, no significant differences in probing depth reduction or frequency of bleeding were observed at any time point. It is concluded that the development of clefts or craters during the early stages of healing had no adverse effect on the eventual establishment of periodontal health. / Periodontol 1990;61:564-570. mm

and 22%. When

areas

Key Words: Gingival/anatomy;- soft tissue/anatomy; periodontal diseases/diagnosis; interdental clefts; interdental craters; periodontitis/surgery

In

surgical therapy of deep periodontal pockets, it is well accepted that flaps, replaced in their original position, may heal with the development of interdental soft tissue craters. This has been described as a postoperative complication of the modified Widman flap procedure.1-2 More recently, Renvert et al.,3 in a comparative study of non-surgical and surgical treatment of intra-osseous defects, documented the frequent occurrence of postoperative soft tissue craters following replaced flap surgery in spite of careful attempts at

wound closure.

Although crater formation is a frequent complication of flap surgery, it has been stated that, if meticulous oral hygiene is maintained, the interdental tissues will repair over a few months with gain rather than loss of attachment.1,2 Nevertheless, concern over the development of interdental soft tissue cratering continues to be expressed in the periodontal literature.4-6

*Periodontal and Preventive Dentistry Unit, University of Glasgow Dental and School, Glasgow, United Kingdom. ^Statistics and Community Medicine, University of Glasgow.

Hospital

While the

occurrence

of soft tissue defects is well doc-

umented, their etiology remains speculative. Many factors

may, in theory, influence the healing response of the interdental soft tissue after repositioned (replaced) flap surgery. These include the amount of underlying bony support, the amount of dead space enclosed by the flaps, and the degree of protection afforded the wound. It is postulated that the presence of soft tissue defects is likely to prejudice interdental plaque control. Also, postoperative esthetics may be compromised in the anterior dentition. The present study was carried out to evaluate interdental soft tissue healing following repositioned (replaced)

flap surgical techniques. Specifically, answers were sought to the following questions:

1. How often do interdental soft tissue defects arise and what is their capacity for repair? 2. Is the subsequent development of a soft tissue defect related to pre-operative probing depth, the presence and topography of an underlying bone defect, or the use of a

periodontal dressing?

Volume 61 Number 9

JENKINS, WRAGG, GILMOUR

565

3. Do these soft tissue defects interfere with the establishment of periodontal health after surgical treatment?

MATERIALS AND METHODS Protocol Twenty-one patients, 6 males and 15 females aged 30 to 57 years (mean age, 40), were judged to satisfy the criteria for inclusion in the present study. That is, upon completion of a course of scaling, root planing, and oral hygiene instruction, these patients, although achieving good standards of plaque control, had persistent, deep, bleeding pockets. They were, thereby, judged to require open flap curettage to give improved access for root planing. Within this group of patients, a total of 100 interdental areas were identified for inclusion in the study on the following criteria: on probing to the base of the pocket, bleeding occurred at one or both of the adjacent proximal tooth surfaces of each interdental area; and the mean Plaque Index7 of the experimental tooth surfaces was 0.24 (S.D., 0.45). Interdental areas distal to the first molar teeth were excluded from the study because of the likely difficulty of ensuring good wound closure. Interdental areas with associated furcation lesions were also excluded because of the difficulty of performing adequate debridement. None of the selected patients was affected by systemic disorders likely to affect the healing response. A total of 46 surgical procedures were carried out, some patients having more than one surgical procedure. Access to root surfaces and bone margins was obtained by raising buccal and lingual flaps. Intra-sulcular marginal incisions were used. Vertical relieving incisions were made one tooth unit away from the nearest test papilla, only if judged necessary for proper access to the surgical site. The undersurfaces of flap margins were trimmed to remove loosely adherent granulation tissues. The bone surface was debrided of granulation tissue. No osseous contouring was carried

Experimental

Following root planing, complete interproximal flap adaptation was attempted by the insertion of interrupted interdental black silk sutures. Coe-pak$ dressing was used in every alternate surgical procedure; 23 operations (51 interdental areas) with, and 23 operations (49 interdental areas) without dressings. Dressing and sutures were removed 1 week postoperatively. Patients were advised to exercise caution when brushing their teeth for the first 2 postoperout.

ative weeks and 0.2% Chlorhexidine mouthwash was prescribed for up to 2 months. Postoperative scaling, polishing, and oral hygiene re-instruction was provided according to individual needs for the duration of the study. The protocol for this study was approved by the Dental Ethics Committee of Greater Glasgow Health Board. *Coe Laboratories,

Chicago,

IL.

1. Silicone elastomer interdental space by syringe.

Figure

impression material is deposited

within the

Data Collection The maximum probing depth of each interdental area was recorded to the nearest millimeter using a Williams probe pre-operatively and at 1, 3, and 6 months postoperatively. The presence or absence of bleeding on probing to the bases of the pockets at each interdental area was recorded pre-operatively and at 1, 3, and 6 months postoperatively. Before wound closure, interdental bone contours were assessed. According to the bony configuration present, each interdental area was labelled as one of the following: interdental bone crater; hemiseptum; 2-walled angular defect; 3-walled angular defect; or no bone defect. The description chosen was the one which most accurately fitted the interdental bone contour. Furthermore, unless there was a bone defect of at least 1 mm depth, the interdental area was classified "no bone defect." After the wound had been sutured, a probe was inserted through the pocket orifice to the bony base of the "pocket," buccally and lingually, at each proximal surface, and the maximum "probing bone depth," was recorded for that interdental area. At each postoperative visit, each interdental space was examined for the presence of a "crater" or "cleft." A crater was defined as a visible depression within the interdental gingival tissue, at least 1 mm in depth. A cleft was defined as a soft tissue interdental defect where there was no visible concavity but the buccal and lingual interdental gingival tissues could be separated with a probe to a depth of at least 1 mm. All clefts were measured to the nearest millimeter using a Williams probe. However, where a crater was identified or suspected, an impression was taken in a syringeable, heavy-bodied, addition cured, silicone elastomer (Fig. 1). On removal from the mouth the impression was poured in dental stone. The stone replicas of interdental spaces were carefully

J Periodontol 566

INTERDENTAL SOFT TISSUE DEFECTS AFTER SURGERY

September 1990

measured. In this case, points 1 and 2 correspond to the of the pseudo-papilla, and point 3 to the base of the defect. Each point is observed in turn and the coordinates sent to the computer. When observations are complete, the computer uses the 3-dimensional coordinates to construct an imaginary line between points 1 and 2 and from this line to drop a perpendicular to point 3. The length of the perpendicular is calculated to give the depth of the defect to the nearest 0.001 mm. Four replicate measurements of each crater were made giving a standard deviation of 0.18 mm in this study. The diagnosis of a crater was made only when the depth of the defect on the stone model amounted to 1 mm or more at the 1-month follow-up examination. All crater sites, so defined, were followed up at the 3- and 6-month visits by further impressions and Reflex Microscope analyses as previously described. All the surgical treatment and clinical measurements were carried out by the same individual and the microscopic analyses by another individual. All 21 patients attended for the 1-month follow-up examination. Nineteen patients went on to complete the full schedule of follow-up examinations; the other two patients were unable to attend at 3 and 6 months. Thus, for the 3and 6-month follow-up examinations, data were available for only 91 out of the 100 interdental areas. Of the 9 interdental areas with missing data, one area had a cleft and one a crater at the 1-month follow-up. Data from these 9 areas have been omitted from all the analyses which relate to changes over time.

tips

Figure 3.

Sectional

drawing of the stone replica of an interdental crater

(with tooth outline shown for orientation). Points

1 and 2 represent the to point 3

tips of the pseudo-papilla. The length of the perpendicular represents the depth of the crater.

trimmed (Fig. 2) and crater depths were measured by the Reflex Microscope.§ This is a modified stereoscopic optical microscope in which the x, y, and axes are linked by optical position sensors to a microcomputer. Figure 3 illustrates the principle of the measurement technique used in this study. The object to be observed is manipulated in the x, y, and axes such that a small diameter light spot, which appears in the field of view of the microscope, seems to be coincident with the first of the object points to be sReflex Measurement Ltd., London, United

Kingdom.

Statistical Methods The data were analysed using the Minitab statistical package.8 In Tables 1 through 6, the data are summarized in terms of the 100 individual interdental areas, but all of the formal analyses have used the patient as the unit of analysis.

Volume 61 Number 9

JENKINS, WRAGG,

Table 1. The Depths of Clefts and Craters at the Examinations

1, 3,

and 6 Month

Follow-up

Depth (mm) 1 Month

Clefts

(12)

Range

Mean (S.D.) Craters (29)

Range Mean

(S.D.)

3 Months

1.02 1.57

3.0

(0.62) -

2.33

(0.42) -

0.0 1.33 0.23 0.92

3.0

Interdental Area

6 Months

(0.89) -

1.92

(0.46) -

0.0 1.33 0.21 0.68

3.0

Dressing

No. 6

-3 +3

(0.89) -

1-2

7

1.48

(0.39)

Thus for each of the 21 patients, the mean value of each variable was computed over all appropriate interdental areas and the analysis was based on comparisons of these mean values,9 using paired f-tests10 if the means were normally distributed and the Signed Ranks test10 otherwise.

=

Etiology of Soft Tissue Defects Table 2 shows how the experimental interdental areas were distributed within the 21 patient sample, and the allocation of dressing and occurrence of soft tissue defects at the 1month follow-up examination. The interdental area between the lower central incisors is represented only twice. However, all other types of interdental area are represented in Table 2 between 6 and 15 times. The allocation of dressings to the various types of interdental area, although carried out for every alternate surgical procedure, led to a fairly equal distribution of "dressing" and "no dressing" to each type of interdental area except the upper 5-6 space where dressings were used 6 out of 7 times. Generally, there was no obvious association between the use of periodontal dressing

1

Crater 2 0

3 1

0

0

2

1

2 2 3

-3 +4 -3 +3 -5 +5

1 0

0 1

2 4

0

3-4

10

0

I

4-5

8

-5 +3

3 2

0 0

2

^5-6

7

1

0 1

0

0

1 5

0 0

0 0

+2

2 0 4 2

0 0

-5

5

+6

5

0 1

1 0 0 0

+6 -

RESULTS

Cleft 0

6

J

Upper

Soft Tissue Defect None 1 2

2- 3

-

Occurrence and Healing of Soft Tissue Defects At the 1-month follow-up examination, out of a total of 100 interdental areas, 13 clefts and 30 soft tissue craters were identified. Table 1 shows the depths of these soft tissue defects and the changes which had occurred by the 3- and 6-month follow-up examinations. The depths of clefts ranged from 1 to 3 mm at the 1-month follow-up examination and there was some evidence for a reduction in depth of clefts over time, mean values reducing from 1.75 mm at the 1-month follow-up examination to 1.33 mm at the 3-month follow-up examination with no further change-at the 6-month stage. However, looking at the data qualitatively, the depth of cleft was reduced at the 3-month examination at only 4 out of 12 sites, the other 8 clefts exhibiting no change. The deepest cleft, which measured 3 mm after 1 month, also measured 3 mm at 6 months. Craters, on the other hand, showed a strong tendency to reduce in depth during the 6-month healing interval. At 1-month, the mean depth was 1.57 mm reducing after 6 months to 0.68 mm (Paired í-test, t 11.6, < 0.001). Whereas at 1 month all 30 craters measured 1.02 mm or more, by 6 months only 3 defects remained whose depth exceeded 1 mm.

567

Table 2. Distribution of Experimental Interdental Areas, Allocation of Periodontal Dressing, and Occurrence of Soft Tissue Interdental Defects at the 1-Month Follow-up Examination

Location* 1.0 1.75

GILMOUR

1-1

2

-2 +0

1-2

7

-5

2-3

11

Lower

I

3-4

15

-8 ±7

3 6

3 0

2 1

4- 5

11

-5 +6

2 3

1 1

-4 +6

2 3

2 2 0

-49 + 51

28

^5-6

10

Total

100

1

2 2 16 14

29

*1-1 represents the interdental area between the central incisors; 1-2, the interdental area between central and lateral incisors, etc. Table 3. Mean Probing Depths Pre-Operatively and Mean Probing Bone Depths Immediately Postoperatively for Interdental Areas Which, at the 1-Month Follow-up Examination, Presented With Clefts, Soft Tissue Craters or No Soft Tissue Defects

Soft Tissue Defect None

Cleft Crater All

(57) (13) (30) (100)

Probing Depth (mm) Mean (SD) 5.1 5.8 5.9 5.3

(2.2) (1.0) (1.4) (1.6)

Probing

Bone Depth Mean (SD) 4.7 5.7 6.0 5.2

(mm)

(1.7) (1.2) (1.2) (1.6)

and the subsequent occurrence of interdental soft tissue defects. Table 3 shows the mean probing depths pre-operatively and the mean probing bone depths immediately postoperatively for interdental areas which at the 1-month followup examination presented with clefts, craters, or no defect. In each case, the mean pre-operative probing depth (distance from gingival margin to base of pocket) was similar to the mean postoperative probing bone depth (distance from gingival margin to underlying bone in the sutured wound). The probing depths at areas presenting with craters, clefts, and no defect were averaged within each patient and compared using paired r-tests. This showed that areas which

568

J Periodontol 1990

September

INTERDENTAL SOFT TISSUE DEFECTS AFTER SURGERY

Table 4. The Distribution of Different Types of Bone Defect With Respect to the Subsequent Occurrence of Soft Tissue Defects at the 1-Month Follow-up Examination

Soft Tissue Defect None

None Cleft Crater All

(57) (13) (30) (100)

Bone defect Hemiseptum 2-Walled

3-Walled

Crater 15 6 10

29

5 10 10

44

8

7

*(4.6(1.6)) (6.5(1.1)) (6.6(1.5)) (6.5(2.0)) (5.7(2.1)) in

mm

Probing (%)

Defect

Bleeding

None Cleft Crater

100 100 100

1 Month 14 33 21

3 Months 22 17

6 Months 26 17

17

17

100

19

20

22

Pre-op

31

'Figures in parentheses are the means and standard deviations pre-operative probing depths of each type of bone defect.

Table 6. Frequency of Bleeding on Probing to the Base of the Pocket Pre-operatively and at 1, 3, and 6 Months Postoperatively With Respect to the Occurrence of Soft Tissue Defects at the 1Month Follow-up Examination

All

(50) (12) (29) (91)

on

of

the

pre-operative probing depth (Table 5) was 5.3 reducing to 2.1 mm by the 1-month follow-up examination and to 2.0 mm by the final visit. Since probing depths at follow-up are dependent on pre-operative probing depth, the reduction in probing depth at each site was computed. The mean reduction at 1 month was 3.1 mm for sites The

Table 5. Mean Probing Depths Pre-Operatively and at I, 3, and 6 Months Postoperatively With Respect to the Occurrence of Soft Tissue Defects at the 1-Month Follow-up Examination

Defect None Cleft Crater All

Probing Depth (50)

(12) (29) (91)

1 month

Pre-op 4.9 (2.3)

5.8 5.8 5.3

1.8 2.4 2.5

(1.1) (1.4) (1.9)

2.1

(0.7) (0.8) (0.8) (0.8)

in

mm mean

(S.D.)

3 months 1.9 (0.7) 2.0 (0.4) 2.4 (0.9) 2.1

6 months 1.9 (0.6) 2.0 (0.0) 2.2 (0.7)

(0.8)

2.0

mean

mm

(0.6)

gave rise to soft tissue craters had significantly deeper pockets pre-operatively than areas with no defect (t 2.8, 0.02). Likewise, comparison of probing bone depths revealed that areas giving rise to craters had significantly deeper probing bone depths immediately after operation than areas with no defect (t 3.2,