Tissue management in fixed prosthodontics

Gingival displacement: Survey results of dentists' practice procedures

STATEMENT OF PROBLEM

A high percentage of fixed prosthodontic restorations require a subgingival margin placement, which requires the practice of gingival displacement or a deflection procedure to replicate the margins in impression.

PURPOSE

The purpose of this study was to learn the different gingival displacement techniques that are currently used by dentists in their practice and to compare the current concepts of gingival displacement with previously published articles.

MATERIALS AND METHODS

A survey of questions pertaining to gingival deflection methods was distributed as part of continuing education (CE) course material to dentists attending CE meetings in 7 states in the U.S. and 1 Canadian province. Question topics included initial patient assessment procedures, gingival displacement methods, dentist's knowledge and assessment of systemic manifestations, and brand names of materials used.

RESULTS

Ninety-four percent of the participants were general practitioners with 24.11 ± 12.5 years of experience. Ninety-two percent used gingival displacement cords, while 20.2% used a soft tissue laser and 32% used electrosurgery as an adjunct. Sixty percent of the dentists used displacement cords impregnated with a medicament. Of the preimpregnated cords, 29% were impregnated with epinephrine, 13% with aluminum chloride, and 18% with aluminum potassium sulfate.

CONCLUSION

The study showed a steady decrease compared with results of previously published articles in the use of epinephrine as a gingival deflection medicament.

The effect of gingival retraction procedures on periodontal indices and crevicular fluid cytokine levels: a pilot study

PURPOSE

The purpose of this study was to examine the effects of placement of retraction cord subgingivally upon periodontal indices including plaque index (PI), gingival index (GI), pocket depth (PD), bleeding on probing (BOP), and attachment level (AL), as well as gingival crevicular fluid (GCF) and TNF-alpha levels.

METHODS

Ten teeth in 6 patients who were periodontally healthy were selected. These teeth had pocket depths of 3 mm or less, no evidence of significant loss of attachment, BOP, or plaque accumulation. The patients each received an oral prophylaxis. The following week, baseline measurements of periodontal indices and TNF-alpha were taken and the retraction cord was placed for 15 minutes. Following removal, the patients were dismissed. The periodontal indices measured included PI, GI, PD, BOP, and AL. In addition, the levels of TNF-alpha in GCF, were investigated. These measurements were made before gingival retraction as a baseline and on the 1st, 3rd, 7th, 14th, and 28th days post retraction.

RESULTS

A repeated measures ANOVA showed that TNF-alpha levels in GCF were significantly increased at all five intervals after gingival retraction compared to the baseline. The mean TNF-alpha level peaked at Day 1 (0.90 +/- 0.62), then declined at Days 3 (0.53 +/- 0.16), 7 (0.43 +/- 0.08), 14 (0.47 +/- 0.10), and 28 (0.43 +/- 0.08) but was still elevated 54% above baseline at Day 28, p < 0.01. The GI was significantly elevated at Day 1 (0.9 +/- 0.49), p < 0.01; Day 3 (0.53 +/- 0.32); and Day 7 (0.33 +/- 0.33), p < 0.05. Unlike TNF-alpha, GI recovered to the baseline by day 14. Other periodontal parameters, PI, PD, BOP, and AL were not significantly altered by the gingival retraction procedure.

CONCLUSION

This pilot study supports the previous research that gingival retraction causes an acute injury that heals clinically in 2 weeks as is indicated by the GI. It also provides the first evidence that gingival retraction results in an elevation of the proinflammatory cytokine, TNF-alpha, in GCF.

Current concepts in gingival displacement

Gingival displacement is an important procedure with fabricating indirect restorations. Gingival displacement is relatively simple and effective when dealing with healthy gingival tissues and when margins are properly placed a short distance into the sulcus. Several techniques have proven to be relatively predictable, safe,and efficacious. No scientific evidence has established the superiority of one technique over the others, so the choice of technique depends on the presenting clinical situation and operator preference.

In vitro kinetic study of absorbency of retraction cords

STATEMENT OF PROBLEM

The soaking time required for liquid uptake by retraction cords is a crucial factor in the successful gingival retraction procedure.

PURPOSE

The aim of this investigation was to determine the optimal soaking time for 3 retraction cords of different thickness to ensure adequate uptake of the hemostatic solution.

MATERIAL AND METHODS

Braided ULTRAPAC retraction cords of 3 different thicknesses (No. 00, No. 0, and No. 1) with identical lengths (35 mm) were used. The capability of the cords to absorb liquids was measured by a gravimetric method. Different sulcus retraction solutions (epinephrine, aluminum chloride, and ferric sulfate) were tested, with physiological saline solution used as the control. The cords were soaked for various time intervals (2 seconds; 1, 5, and 60 minutes; and 24 hours) in the medicament solutions at room temperature. Immediately before immersion, air inclusions that may have inhibited the inner moistening of the cords were manually pressed out. In each of the 4 treatment groups, 75 pieces of cord were tested by determining the grams of fluid absorbed by grams of dry cord (gram/gram). Before the cord was weighed, excess fluid accumulating on the outer surface of the cord was removed by filter paper saturated in the corresponding test solution. The data were analyzed by F test analysis, and P<.05 was regarded as significant.

RESULTS

In each group, regardless of the cord type (No. 00, No. 0, or No. 1) or medicament solutions tested, the amount of fluid absorbed increased with the soaking time, but to different extents. A logarithmic relationship in a linear plot between the amount of fluid absorbed and the soaking time was demonstrated. The relationship established offered an exact determination of both the rate and the saturation level of liquid uptake. The rate of liquid uptake calculated from the saturation equations exhibited significant correlation with the cord thickness (P<.05). The saturation levels of the solutions did not show correlation with the cord thickness (P>.30).

CONCLUSION

Within the limitations of this study, the results indicated that 20 minutes of soaking time was necessary for saturation of the cords before use, provided that air trapped within the cords was removed. In addition to the soaking time, the saturation of the cords with the solutions largely depended on the wetting of the cords.

Maintaining and enhancing gingival architecture in fixed prosthodontics

The long-term success of fixed prosthodontic restorations is greatly dependent upon the health and stability of the surrounding periodontal structures. This article deals with the interrelationship between fixed prosthodontic procedures and the stability and health of the periodontium. The commonly encountered problem of alterations in gingival architecture is examined in relation to tooth preparation as well as soft tissue preparation. In addition, the ability of the provisional restoration to guide soft tissue form is discussed as well as the role of the final restoration in providing long-term tissue maintenance. Key factors such as margin placement, tissue damage during tooth preparation, the role of the provisional restoration, tissue injury during impression procedures, crown contour, pontic design, and embrasure design are covered in detail.

Margin design for esthetic posterior metal ceramic crowns

Variations in margin designs for ceramic metal restorations have been used to fulfill the many requirements for such restorations. The trend in our population toward greater esthetic awareness places increased emphasis on esthetics. This trend necessitates a high level of esthetics in posterior restorations. Commonly used posterior margin designs have been described and their inherent weaknesses and strengths have been reviewed. An alternative design has been proposed with its advantages in esthetics, tissue compatibility, cleansibility, and versatility. The clinical and laboratory procedures for this design have been described.

Tissue displacement methods in fixed prosthodontics

The various methods to accomplish gingival displacement have been described. The techniques have been noted and their relative advantages and disadvantages summarized. The practicing dentist can use this review to make better informed decisions regarding the method he or she chooses for the treatment of a particular patient.

Exposing the gingival margin: a systematic approach for the control of hemorrhage

Consistent and successful gingival deflection can be performed by controlling hemorrhage first. A systematic approach with contemporary materials has been described for various clinical situations to aid the dentist in the selection of an appropriate technique when gingival deflection is performed.

Clinical effectiveness of mechanical-chemical tissue displacement methods

The following conclusions were made after statistical analysis. There was no significant difference between racemic epinephrine cord and aluminum sulfate cord. Both racemic epinephrine cord and aluminum sulfate cord were more effective than nonmedicated cord. There was no difference between dry cord and water-saturated cord. Hemorrhage control with a cord saturated in Hemodent was more effective than water-saturated or dry cords. The racemic epinephrine cord was not superior to the aluminum sulfate cord, so the dentist could eliminate a cord with potential systemic effects and substitute the more innocuous cord. Hemodent approximately doubled the hemostasis success of any cord used in this study.

Comparative study of gingival retraction methods

The effects of electrosurgery, retraction cord, and the rotary gingival curettage technique were tested clinically and histologically in dogs. Postoperative periods analyzed ranged from 6 hours to 14 days. All methods induced some kind of minor damage. Recession of clinical magnitude was induced only by rotary gingival curettage. Apical migration of the junctional epithelium was not seen.

A comparison of cord gingival displacement with the gingitage technique

Fifteen young adult dogs were divided into three groups representing 0, 7- and 21-day healing periods. Randomly selected cuspid teeth were used to compare cord gingival displacement and gingitage techniques for subgingival tooth preparation and impression making. Clinical and histologic measurements were used as a basis for comparison. Results indicate that (1) the experimental teeth were clinically healthy at the beginning of the experiment, (2) clinical health of the gingival tissues was controlled throughout the course of the experiment, and (3) within this experimental setting, there was no significant difference between the cord gingival displacement technique and the gingitage technique.

Analysis of the geometry of finishing lines for full crown restorations

The geometry exhibiting the least marginal discrepancy in this investigation was the shoulder of the slightly oversize casting (Fig. 4). This was significantly better (p = .05) than the oversize bevel, the control shoulder, or the control bevel.