Gingival tissue response to rotary curettage

LEE AND

Thresher, R. W., and S&to, G. E.. The stress analysis of human teeth. J Biomech 6:443, 1973. S&a, L. G., Shillingburg, H. T.. and Kerr, P. A.: Finite element analysis of dental structures-Axisymmetric and plane stress idealizations. J Biomed Mater Res 9:237, 1975. Yettram, A. L.. Wright, K. W. J., and Pickard, H. M.: Finite element stress analysis of the crowns of normal and restored teeth. ~J Dent Res 55:1004, 1970. Phillips, R. W.: Skinner’s Science ot Dental Materials, ed 7. Philadelphia, 1973. W. B. Saunders Co., pp 49-51. Craig, R., Peyton, F., and Johnson, D.: Compression properlies of enamel, dental cements and gold. J Dent Res 40:936. 1961. Bowen, R., and Rodriguez, M.. Tensile strength and modulus of elasticity of tooth structure and several restorative materials J Am Dent Assoc 64~378, 1962. hrends, J.: Schuthof, J., and Jongebloed. W. I,.: Mineral properties of the outer tooth surface. in Leach, S. A., editor: Dental Plaque and Surface Interactions in the Oral Cavity. Cheshire, England, 1979, Imperial Chemical Industries Ltd., pp 251-272. Powers, J. M., Craig, R. G., and Ludema, K. C.: Frictional behavior and surface failure of human t-name]. J Dent Re\ 52:1x27, 1971.

23. 24.

2s

16 27. 28

EAKLE

Brady, J. M., and Woody, R. D.: Scanning microscopy of cervical erosion. J Am Dent Assoc 94:726, 1977. Xhonga, F. A., Wolcott, R. B., and Sognnaes, R. F.: Clinical measurements of dental erosion progress. J Am Dent Assoc 84:577. 1972. Xhonga, F A., and Sognnaes, R. F.: Dental erosion: Progress of erosion measured clinically after various fluoride applications J Am Dent Assoc 87:1223, 1973. Xhonga, F. :I.. Bruxism and irs effect on the teeth. J Oral Rehabil 4~65. 1977 Xhonga, F. A, and Van Herle, A.: The influence of hyperthyroldism on dental erosions. Oral Surg 36~349, 1973. Sognnaes. R. F., Wolcott, R. B., and Xhonga, F. A.: Erosionhke patterns occurring in association with other dental conditwn$. J Am Dent Assoc 84:571, 1972.

Gingival tissue response to rotary curettage Fred W. Kamansky, D.D.S.,* Thomas R. Tempel, D.D.S., M.S.Ed.,** and Arthur C. Post, D.D.S., M.Ed.*** Walter

Reed Army Medical Center, Washington, D.C.

T

he management of gingival tissues during subgingival preparation of teeth for fixed prostheses varies in the technique used and the degree of effectiveness. High-frequency electrosurgery and lateral gingival tissue displacement achieved with a variety of chemically treated retraction cords are now the most common methods for tissue management of prepared teeth. One approach to gingival tissue management during fixed prosthodontic procedures is rotary gingival curettage. This technique? uses a specially designed rotary diamond instrument to remove a portion of the inner epithelial lining of the gingival sulcus during the

I‘hr opinions or assertions herein are the private views of the authors ,ind are not to be construed as official or as reflecting the views of ~hc I.~.$. Departments of the Army, Naby. or Defense. Subrnittrd in partial fulfillment of the requirements of the Fixed i’rosthodontirs Rrsidenc) Program. Walter Reed .4rmy Medical (:entrr, Washington. D.C “! Zrxnmander (DC:) USN; Prosthodontirs Dept.. Branch Dental (:linic NDC, N.4S North Island. San Diego. C.4. **Colone!, DC. LrSA, 1.1 S. Army Hospital, \C’orzburg. West t Germany. *‘*Formerly, Colonel. DC, USA; Augsburg, West Germany; prescntly, Colonel, DC, 17% (retired). fInqrah,+m. R. Perconal communication. 1978

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placement of the finish line on tooth preparations. Tupac and Neacy’ conducted a study on dogs to compare cord gingival displacement with the rotary gingitage technique. They found no significant difference clinically or histologically between the two methods.

Amsterdam* suggested the use of rotary curettage in conjunction with the preparation of teeth for fixed prostheses. However, he observed that the rotating diamond instrument provided questionable tactile guidance while locating the position of the rotary instrument in the gingival sulcus during the procedure. The rate of healing of the gingival tissues after a surgical curettage procedure is relevant to the rotary curettage technique. Moskow3 reported that complete coverage of the debrided tissue with epithelium was seen within 7 days after gingival curettage on dogs. Blass and Lite4 found microscopically that complete healing was seen within 10 days after curettage on a healthy patient. Although complete healing of the gingiva can be predicted after rotary curettage, the human clinical application of the procedure could have collateral factors that affect the ultimate clinical response. The SEPTEMBER

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Fig. 1. Approximate dual reference depression location on mesial-facial and distal-facial tooth preparation surface.

changing subgingival tissue architecture that surrounds the natural dentition could lead to an unintentional encroachment on the attachment apparatus with a high-speed rotary instrument. Gingival recession, increased sulcular depth, and prolonged healing response with or without persistent gingival inflammation could be adverse reactions observed with such a traumatic episode to the gingival tissues. To date no study has been published in regard to gingival tissue response to rotary curettage on humans. This investigation compares human gingival tissue response to rotary curettage with chemically treated cord lateral tissue displacement. MATERIAL

AND METHODS

Ten men scheduled for treatment with maxillary anterior fixed partial dentures were selected for this study. Ages ranged from 22 to 37 years with a mean age of 25.7 years. Full coverage porcelain-fused-tometal preparations were used. The gingival tissue of one abutment was treated with rotary curettage, while the tissue of the other abutment was managed with lateral tissue displacement. The periodontal index5 was used to determine the level of inflammation and thus the eligibility of subjects for this study. All patients were free of gingival inflammation prior to the procedure. Abutments were required to have adequate zones of attached gingiva. Reference depressions were prepared with a No. % round bur on each abutment preparation in the following locations: mesial-facial; distal-facial; and midlingual (Figs. 1 and 2). The first measurement (Ll) was made to the probed depth of the clinical sulcus THE JOURNAL

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Fig. 2. Approximate dual reference depression location on midlingual tooth preparation surface.

(Fig. 3). A second measurement (LZ) was made to the crest of the free gingiva (Fig. 3). A modified Boley gauge” was used to determine measurements to 0.1 mm (Fig. 4). A crosshatch extension was provided so that the instrument could be reoriented in the reference depressions at each measurement interval. The dual depressions allowed identical measurements to be made at each reference area (Figs. 1 and 2). Measurements were made at the following time intervals: prior to the procedure, 14 days after the procedure, and 90 days after the procedure. A preview of the architecture of the gingival structures that surrounded the abutment teeth was carefully evaluated with a periodontal probe prior to tissue manipulation. Rotary gingival curettage diamond instruments (Abrasive Technology, Inc., Premier Dental Products Co., Norristown, Pa.) were used for the tooth and tissue preparation. Water-moistened Hemodent No. 9 gingival retraction cords (Premier Products Co.) were placed passively in the gingival sulcus for hemostatic control of the tissues. The same retraction agents were used for lateral displacement of the gingiva prior to placement of the preparation finish line within the sulcus. Final impressions were made with a polysulfide rubber material. Well-contoured self-cured acrylic resin provisional fixed prostheses were placed with a zinc oxide-eugenol luting material during the 0- to-14-day interval. Completed fixed prostheses were cemented temporarily with a zinc oxide-eugenol cement at the 1Cday interval. At the 90-day interval, final measurements were made and the fixed prostheses were cemented with zinc phosphate cement. All tooth preparations, tissue management, and 381

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TEMPEL,

AND

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Fig. 4. Modified Boley gauge periodontal probe that measures to 0.1 mm. A, Drawing. B, Photograph.

Fig. 3, Biometric application of modified Boley gauge periodontal probe. LZ = Clinical sulcus depth measurement; 12 = gingival crest measurement.

measurements were accomplished by one operator (F.K.). A paired t test was used to evaluate the differences between the two methods of tissue management. Differences at p < .05 were considered significant.

RESULTS Methods of tissue management are presented in Table I. The following results were determined at the p < .05 level: 1. Rotary curettage (RC) showed significantly less facial gingival crest height changes than did the lateral displacement (LD) method. The mean gingival height loss was 0.15 mm (RC) and 0.29 mm LD, respectively. The palatal tissues showed no significant difference between the two methods. The mean palatal-gingival crest height changes were 0.1 mm RC and 0.12 mm LD. 2. A statistically significant difference was found in the response of the facial gingival sulcus to the two methods. Rotary curettage was responsible for a greater increase in sulcus depth than lateral displacement. The mean facial-sulcus depth increase was 0.15 mm 382

RC and 0.035 mm LD, respectively. The palatal tissues again displayed no significant differences in sulcus depth changes between the two methods of tissue management. The mean palatal-sulcus depth change was 0.03 mm RC compared with 0.02 mm LD. 3. The net clinical sulcus depth measurement was determined by calculating the differences between the gingival crest and the sulcus depth changes. A statistical dissimilarity was found between the two methods of tissue management when applied to the labial tissues. Rotary curettage of the abutment teeth showed a slight increase, while lateral displacement displayed a decrease in depth of the labial gingival sulcus. The palatal gingival sulcus decreased in depth and showed no significant differences between the two methods. DISCUSSION The values for the reaction of the facial gingival crest tissues with the two methods of tissue management suggested that rotary curettage did not cause tissues to recede any more unfavorably than the lateral displacement approach. The apical portion of the facial sulcular tissues reacted significantly differently to both methods. Rotary curettage caused sulcular measurements to increase over those observed with the lateral displacement technique. A possible explanation is that rotary curettage caused a disruption of the apical sulcular epitheliurn that resulted in apical repositioning of the tissues after repair. Although caution was exercised to avoid injuring the attachment apparatus of the gingival SEPTEMBER

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Table I. Methods

CURETTAGE

of tissue management

and resultant

changes Change measured

Gingival

Rotary curettage (mean) Lateral displacement (mean) t test df Significant at p < .05

crest height

Sulcus depth

Net clinical

sulcus depth

Facial

Palatal

Facial

Palatal

Facial

Palatal

+.I5 mm +.29 mm 2.833 19 Yes

+.lO mm +.12 mm ,688 9 No

+.15 mm +.035 mm -4.196 19 Yes

+.03 mm +.02 mm 1.5 9 No

+.005 mm -.21 mm -3.487 19 Yes

-.07 mm -.08 mm -.709 9 No

d/ = Degrees of freedom; + = increase in measurement; - = decrease in measurement.

tissue, the lack of tactile sensation of the rotary instrument within the sulcus may be a contributory factor to this problem. Moving the high-speed diamond point through the gingival sulcus of the facial tissues was technically more difficult than through the palatal areas. The use of a periodontal probe to preview the depth and architecture of the gingival tissues prior to the rotary curettage technique is viewed as essential to minimize contact with the underlying gingival attachment. Statistically significant differences were not found between the response of the palatal tissues to the two methods. The thicker palatal tissues responded more favorably to rotary curettage in all respects than the thinner facial tissues. The observed differences between the two methods of tissue management may not be of clinical significance, because neither method adversely affected the net depth of the clinical gingival sulcus. Within the scope of this study, the proper use of rotary curettage instruments resulted in an efficient and predictable method by which gingival retraction for impression making was achieved. The gingival tissues should possess adequate attached gingiva and be structurally sound to allow an optimal healing response. The use of the rotary curettage procedure on thin fragile facial tissues is questionable, because tissue tears could occur with a resultant loss of tissue after healing. SUMMARY

AND CONCLUSIONS

A clinical study to compare gingival response to two methods of tissue retraction was completed on 10 patients who required maxillary anterior fixed prostheses. A modified Boley gauge periodontal probe was used to make the biometric measurements. The gingival crest and clinical sulcus measurements were made on designated facial and palatal tissue reference points prior to the procedure and 14 and 90 days after the procedure. Within the limits of this study, the following conclusions were made: 1. Rotary curettage compared favorably with the lateral displacement method of tissue retraction in the amount of gingival crest recession. THE JOURNAL

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2. Rotary curettage caused an apparent disruption of the apical sulcular and attachment epithelium, with an apical repositioning of the tissues after repair and stabilization. The lack of tactile sensation of the high-speed rotating instrument contributed to this problem. The recorded sulcus depth changes were not regarded as clinically significant. 3. Changes in gingival crest and clinical sulcus measurements were not found on the palatal tissues with either method of tissue management. Thicker palatal tissues responded more favorably to rotary curettage than thinner facial tissues. 4. Rotary curettage was an efficient and predictable technique in management of the gingival sulcus for impression-making procedures for fixed prostheses. 5. Long-term clinical observations with a histologic assessment of the healing respdnse to the rotary curettage procedure would be beneficial in further determination of the efficacy of the technique. The assistance of Lieutenant Colonel Jay D. Shulman and Mr. Richard A. Stroh, United States Army Trimis Agency, in the statistical analysis of the data is gratefully acknowleeed.

REFERENCES 1. Tupac, R. G., and Neacy, K.: A comparison o cord gingival displacement with the gingitage technique. J PKOYTHET DFAT 46:509, 1981. 2. Amsterdam, M.: Lectures in stomatognathology Temple Umversity School of Dentistry, 1954. 3. Moskow, B. S.: Response of the gingival sulcus to instrumentation-A histological investigation of gingival curettage. J Periodontol 35:112, 1964. 4. Blass, J. L., and Lite, T.: Gingival healing following surgical curettage-A histopathologic study. NY State Dent J 25:127, 1959. 5. Cohen, D. W., and Ship, I.: Transactmns of thr conference on clinical niethods in periodontal disease. University of Pennsylvania. J Periodontol 38~582, 1967. 6. Detsch, S. G.: A periodontal probe that measures to one-tenth millimeter. J Periodontol 51:298, 1980.

Refmt requestJto: DR. FRED W. KAMANSKV BRANCH DENTAL CLINIC NDC NAS NORTH ISLAND SAN DIEGO, CA 92135

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