Tips from the lab predictable impressioning


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Tips from the lab predictable impressioning

  1. 1. Tips from the lab Predictable impressioningEQUIPMENT By John C. Cranham, DDS, Chesapeake, Va. ② Control the soft tissue through preliminary W ithin a well-run den- dictability to all indirect esthet- employed to consistently place the tal practice, a direct ic/restorative dental procedures. margin one-half the depth of the mouth preparation and chemotherapeutics relationship exists healthy pocket. If the pocket is 2.5 Starting with a healthy mouth is a between pre- Soft-tissue management mm deep, then the margin should prerequisite of any restorative pro- dictability and positive trends. From time to time, it is necessary be placed 1.2 mm underneath the cedure. Proper preliminary These benefits include increased to control a minor amount of gin- tissue. This will create an invisible mouth preparation should production, decreased overhead, gival bleeding during a restorative margin, and one that exists in a include any and all procedures toM AT E R I A L S increased profitability, decreased procedure. Inadvertently nicking healthy relationship within the get the mouth completely free of stress, and increased happiness of the tissues during margin refine- periodontal structures. disease prior to the final restora- the entire dental team. The better ment does occur occasionally and tive phase. Healthy tissue will we become at doing procedures it is essential to have the ability to Retraction options make our job easier and the final correct the first time, the more we quickly control hemostasis. There are many excellent ways to esthetic/restorative result more can experience the attributes pre- Viscostat from Ultradent dis- retract tissue if the only goal is to predictable. viously mentioned. Becoming pre- pensed from its Dental Infusor is a simply expose the gingival margin. Additionally, chemotherapeutic dictable in our work should be the fast, predictable way to obtain 100 Laser troughing and electrosurgi- agents such as Viscostat (Ultradent primary focus of every dental percent control. cal procedures are both excellent Products, figure 2, below) can beA S S I S TA N T S practice. Without predictability, ways to expose the restorative mar- there is great uncertainty, and Start with an impressable preparation gins. A retraction cord, while more found within uncertainty is a high Most restorative dentists do not time-consuming, can be used to degree of stress. trim their own dies. While many more predictably place the margin For a dental practice that does teaching institutions recommend in the ideal zone within the gingi- any amount of indirect restorative doing this, with consistently excel- val sulcus. dentistry, learning a tried-and-true lent impressions, it is actually an A two-cord technique has been technique that consistently cap- unnecessary step. It is important, described to accomplish this goal. tures the necessary details of an therefore, for dentists to prepare The technique described in this impression is a vital component. teeth in a way that their margins article is a modification of this Yet, after speaking to hundreds of are easily identifiable. We should process utilizing contemporaryFOCUS laboratory owners over the last sev- learn to prepare teeth with a con- materials. eral years, it is obvious that consis- sistent margin design 360 degrees used by directly applying it to the tently excellent impressions are a around the tooth. If a contempo- A step-by-step approach to an tissue to stop any localized bleed- rarity. rary metal ceramic material is your ideal final impression ing. This can also be used to soak restorative choice, then a chamfer ① Start with an impressable preparation the retraction cords (figure 3, Start with healthy tissue margin with the same general look below). This chemical agent It is important to understand that, should be utilized. If you prefer in fabricating an indirect restora- more of a knife-edge or even a tion, the purpose of the impres- shoulder, the key is to develop a sion is not to simply capture the preparation style that your dental details of the hard tissues. The laboratory gets used to seeing. You goal is to also capture the stable want to avoid having a margin that relationship of the gingival tissues. starts as a chamfer, then turns into If we do indirect restorative proce- a knife-edge, and then ends in a dures in the presence of gingival shoulder. These become very diffi- In figure 1 (above), you will see a inflammation, the final restorative cult to read and trim. Preparing tooth prepared for a Captek result will likely be inadequate, no teeth with consistent margin Crown. The preparation has ade- matter how “good” the impres- design will add tremendous pre- quate reduction (as described in (Ferric Sulfate), not only rapidly sion. After final crown placement, dictability in the laboratory repro- Part 1 of this series, printed in achieves hemostasis, but also fixes when the gingival tissues return to duction of your preparations. January) and has been smoothed the tissue, holding it in the retract- normal size, shape, and contour, and polished. The margin design ed position for a longer period of exposure of a margin will occur. Consistent margin placement is that of a chamfer, around the time. This material is an important While the crown may fit fine, the Consistent margin placement is entire circumference of the tooth. component of any restorative den- outcome is likely to be below the key to providing a restoration that Employing this type of prepara- tist’s armamentarium. patient’s esthetic expectations. will meet the esthetic goals of the tion guideline will dramatically Beginning with healthy tissues patient and the optimum health of increase the readability of your ③ Placement of first cord will also simplify the impression- the restorative result. Not prepar- impressions since your laboratory Prior to final margin placement, making process. Bleeding tissues ing far enough into the gingival support will know exactly what it is the first cord should be packed. A can be controlled, but should not sulcus will lead to esthetic prob- looking for. Whatever margin 00 Ultradent cord that has been be “the norm.” Taking patients lems, while going too deep will design you personally prefer, keep- soaked in Viscostat is placed into through proper periodontal pro- invade the biologic width. ing it consistent will increase the the depth of the sulcus (figure 4). cedures and completing all neces- By beginning with healthy tis- quality and predictability of the As shown in figure 5, the goal is to sary preliminary mouth prepara- sue and using normal probing final restorative result. have it perfectly fit once around tion will add tremendous pre- depths, a technique can be 46 Dental Equipment & Materials • May/June 2003
  2. 2. Comprecap, pushing the Expasyl way into an otherwise perfect further into the pocket (figure impression.EQUIPMENT 12). This provides additional retraction by forcing the tissue fur- ⑨ Visually inspect impression ther away from the tooth. When The final step is visual inspection you combine this benefit with the of the impression. Loupes or some additional hemostatic and drying sort of magnification should be gival sulcus (figure 8, above). It properties of this material, used to check the details of the Figure 4 (above), Figure 5 (below) master impression. As previously has hemostatic agents within its Comprecap makes for a very pre- body and also has the ability to dictable method for margin cap- mentioned, all margins should be absorb crevicular fluid. The most ture. visible with a minimum of .5 mm positive clinical effect observed is apical to the marginal tissues (fig-M AT E R I A L S not just great retraction, but a very ⑦ Visually inspect retraction objectives ure 15). dry field. In fact, there seems to be After washing away the Expasyl By combining all of the ele- a complete absence of fluid (simply remove by spraying with a ments of healthy tissue, correct around the preparation — a quali- three-way syringe) and removing preparation design, predictable ty that makes for an ideal impres- the retraction cord, visual inspec- retraction, and highly esthetic the tooth. Pressure should be sion. tion is the final step before taking porcelain contour and color, we applied so that the 00 cord is sit- the impression. This is when the can all achieve excellent clinical ting at the base of the healthy ⑥ Apply pressure with Comprecap doctor should put on his or her results. The outcome can be seen pocket. After dispensing the appropriate loupes and, using excellent light- in this delivered IPS d.SIGNA S S I S TA N T S amount of Expasyl over the retrac- ing, visually inspect the retracted Porcelain to Captek restoration ④ Margin refinement tion cord (figure 9) circumferen- tissue (figure 13, below). All mar- (figures 16 and 17). Once the tissue has been retracted Indirect restorative procedures with the first cord, the margin is can be a highly predictable, highly finished by dropping the margin profitable component of any den- to the top of the cord (figure 6, tal practice. To achieve this, how- below). The placement of the cord ever, the dental team must employ some simple, disciplined steps to achieve consistent results. This article has outlined a step-by-step, Figure 9 (above), Figure 10 (below) highly predictable method ofFOCUS gins should be easily viewable with obtaining an ideal final impres- a minimum of .5 mm of additional sion. tooth structure apical to the mar- Acknowledgment: The author gin. Figure 13 exhibits the ideal would like to thank the technical staff will protect the biologic width and retraction goals. of Dental Arts Laboratories, Inc. in prevent us from going too far into Peoria, Ill., for their excellent ceramic the pocket. This is where this tech- ⑧ Inject with quality impression material artistry in preparation of this case. nique may have an advantage over A polyvinyl impression material Call (800) 227-4142 to contact DAL. laser or electrosurgical retraction. tially around the tooth, a such as Take One from Kerr can Note: For complete information on While other techniques can rapid- Comprecap (figure 10) is placed be utilized to complete the impres- Cranham Dental Seminars, visit ly attain exposure of the restora- over the prepared tooth. sion procedure. While this materi- or tive margin, there is greater risk of Comprecap, made by Roeko, look al has hydrophilic properties, contact Dr. John Cranham’s office at invading the biologic width or like a hollowed-out cotton roll, but every effort should be made to (757) 465-8900. leaving the postoperative margin are open only on one side and are keep the field dry. Dry angles, cot- visible. firmer (figure 11). Once placed ton rolls, and suction should be employed to keep saliva out of the ⑤ Addition of contemporary retraction material field. This is particularly impor- A very popular method of obtain- tant in the mandibular area. When ing ideal retraction involves the injecting (figure 14, below), keep placement of two cords on top of one another within the pocket. This technique follows a similar path, but uses a contemporary dental material called Expasyl (fig- Figure 11 (above), Figure 12 (below) ure 7, below), recently introduced the tip angled at the margin and burnish the material around the tooth. The thixatropic nature of by Kerr. This material has a clay- this material will allow it to flow like consistency that is released over the prepared tooth, the upon itself, eliminating voids, bub- (under pressure) around the gin- patient can bite on the bles, and fins that can find their From top to bottom, Figures 15-17 48 Dental Equipment & Materials • May/June 2003