The ability to efficiently fabricate precise, esthetic provisional restorations can take a restorative practice to another level. For some clinicians, trimming and shaping provisional materials can be the most time-consuming step. A step-wise technique and the use of proper instruments can streamline this process.
	It should be noted that a precise pre-operative matrix and strict adaptation could render a restoration that requires very little trimming; however, all provisional restorations, especially multiple teeth, require some trimming and shaping to establish proper gingival contours.

Technique and materials
	In recent years, bis-acryl provisional materials have become quite versatile for many restorative applications. Modern bis-acryl materials have physical properties that provide direct application for the following:

Single or multiple teeth
	Anterior or posterior restorations
	Partial or full-coverage crowns
	Esthetic reconstructions
	Short- or long-term provisionalization

The most precise and efficient technique currently uses a pre-operative matrix of the unprepared teeth with a thermal-plastic material (single tooth) or silicone putty (multiple teeth). Restorations may be fabricated directly in the mouth or indirectly on a preparation cast.

KOMET USA recently introduced the Thomas R. McDonald, DMD Provisional System Kit. The kit contains five instruments (four tungsten carbide instruments and one honeycomb spiral reinforced diamond disc) and is designed for trimming bis-acryl provisional materials. The bur shapes and fluting designs are selected for ease of use, precision and efficiency.

Single-tooth trimming and shaping procedure
	Following the fabrication and removal of the restoration with 3M ESPE’s Protemp™ Plus (3mespe.com) from the matrix, it is wiped liberally with alcohol gauze, removing the air-inhibited layer. Margins and the proximal contact areas are marked with a wax pencil (Fig. 1). Any voids in the restoration are repaired with flowable composite (Filtek™ Supreme Plus Flowable Restorative from 3M ESPE) before trimming.

A full-coverage or partial-coverage single-tooth restoration is trimmed and shaped with one bur. The fluting design and cross-cutting of H79GE.HP.070 makes this bur well suited for trimming bis-acryl materials without “chattering” and/or “grabbing” the material while rendering a smooth surface. All trimming should be done while viewing the restoration from the inside and straight down onto the margins. The H79GE.HP.070 bur is held parallel to the external surface of the tooth, creating a straight emergence profile.

Trimming begins at the distal-proximal line angle and is continued to the mesial-proximal line angle (Fig. 2).

The bur is reoriented, allowing for trimming below the contact area  (Fig. 3).

Margin trimming is completed and the coronal aspect of the contact area is shaped to remove peripheral excess (Fig. 4).

With the H1.HP.023 round bur, occlusal anatomy is accentuated and internal surfaces are relieved (Fig. 5).

The use of this step-wise technique allows clinicians to trim a single-tooth restoration in less than one minute (Fig. 6). 

Multiple teeth trimming and shaping procedure
	Trimming multiple unit restorations can be a time-consuming experience. Clinicians can avoid inefficiency by orienting the restoration to allow trimming while viewing the margins and by trimming every accessible margin before repositioning the restoration.

Margins and proximal contacts are marked and the restoration is held by the proximal surfaces. From this orientation the entire lingual surface and margins are shaped with the H251ACR.060 bur (Fig. 7), allowing for precise margin shaping and an initial approach to the proximal embrasures.

The restoration is reoriented and the proximal margin (under the contact area) is trimmed carefully with the greatest convexity of the bur (Fig. 8).
	Facial margins are trimmed in the same manner to render a restoration that only requires proximal embrasure contouring and shaping of the pontic space (Fig. 9).

There are many options in the realm of “all porcelain” restorative materials available to today’s cosmetic dentist. But when it comes to veneers, where esthetics are paramount, some of these materials are best left to posterior applications.
	 

FIGS. 1-5 Side view of a leucite-reinforced IPS Empress (Ivoclar Vivadent) veneer case. Dentistry by Dr. Kalfas and lab work by Quint Whipple of Phoenician Dental Studios (Fig. 1). A close-up view of a leucite-reinforced Empress veneer case. Dentistry by Dr. Kalfas and lab work by Quint Whipple of Phoenician Dental Studios (Fig. 2). A front view of a leucite-reinforced Empress veneer case. Dentistry by Dr. Kalfas and lab work by Micro Dental Lab (Fig. 3). A lithium disilicate veneer (IPS e.max) from Ivoclar Vivadent (Fig. 4). A full smile view of an IPS e.max veneer case. Dentistry by Dr. Frankie Shull and lab work by Matt Roberts (Fig. 5).

Click here for a slideshow with larger images of Figs. 1-5.

In your veneer cases, strength is important, yet esthetic outcomes are the highest priority. Your goal is to achieve both. But with all the available options, it can be difficult to determine which veneer material will best meet this goal. This article will give you an overview of what’s available, making it easier for you to determine what works best for your patients and your practice.

It should look natural
	When discussing esthetic properties, our goal with veneers is to mimic, as closely as possible, the properties found in natural enamel. Translucency tops the list of the most important esthetic properties. This quality separates the life-like veneer from the life-less PFM. The flow of light through the enamel layer and into the dentin truly defines vitality in the restoration. Blocking the light, even when a restoration is beautifully finished, is almost always apparent at the margin. The subsequent “dark root,” even though it may be subgingival, can be evident.

For that reason, I will eliminate opaque “all porcelain” cores, such as zirconia and alumina, from this discussion. And because I want to discuss veneers crafted by skilled technicians, I also will not include “no-prep” Cerinate veneers, whose chemistry is guarded and the work outsourced. This brings us to three choices worthy of examination: feldspathic (stacked) porcelain, leucite-reinforced porcelain and lithium disilicate.

What to consider first
	Before discussing material options, we are pressed to identify the qualities important to our veneer goals. In veneering a tooth, we are replacing enamel, that layer of hard, translucent, shaded hydroxyapatite covering the dentin. We therefore need to consider strength, translucency and color management. Proper adhesive bonding of porcelain to dentin dramatically increases the restoration’s strength. However, while we have achieved fabulous esthetic results for years at the hands of highly skilled technicians, advances in technology are occurring mainly in the area of flexural strength.

There can’t be enough emphasis placed on the importance of working with a knowledgeable, skilled and artistic laboratory technician in obtaining optimal results with veneers. The lab technicians need to know their systems, and you need to know your lab. Communication is crucial to success, both with the lab and with your patient.

Feldspathic porcelain has long set the standard for esthetics in dental restoratives. Feldspathic veneers are hand-crafted, meaning the esthetics are dependant entirely on the technician’s artistic skill. Powders of numerous shades and translucencies are brush-applied using either the refractory model or platinum foil techniques. Layering various opacities provides depth and the subsequent distinction of the dentin and enamel layers found in natural teeth.

The draw-back with feldspathic porcelain is two-fold. First is the lack of flexural strength. Although at 90 MPa it is stronger than enamel (50 MPa), it does not compare favorably with newer materials. The percentage of crystalline structure is an important factor in determining the strength of porcelains. The higher the crystalline structure, the more resilient to crack propagation the material will be. At only 20%, feldspathic porcelain is considerably weak, particularly at the thin marginal edges. The second drawback to feldspathic is its high fusing temperature. Subsequent firings of the finished restoration, to add stain or a contact for instance, almost certainly result in fracture.

Option No. 2: Leucite-reinforced ceramics

In the early 1990s we were introduced to leucite-reinforced ceramics. With a higher percentage of crystals (40%), the flexural strength nearly doubles to 140 MPa. The configuration of the leucite crystals inhibits crack propagation. This material comes in several forms: powders, blocks for pressing, and blanks for milling (CAD/CAM). The pressed technique uses the lost wax technique. The restoration is waxed, invested and burnt-out as with cast metal. However, the material, in the form of an ingot, is then melted and pressed into the void with a special plunger at pressure in a pressing furnace.

Remember you are replacing enamel when you are veneering a tooth. Here’s what you need to consider when determining the best veneering material for your patients?

There are many ingot choices, with varying shades and translucency levels. The ingots are monochromatic, however, so characterization is added through cut-backs and layering and firing with powdered leucite-reinforced porcelain. While some prefer milled cores, the pressing procedure creates a slightly stronger restoration, eliminating porosity and inconsistencies.

Option No. 3: Lithium disilicate porcelain

The final material is lithium disilicate porcelain. Similar to the leucite-reinforced material, this may be pressed or milled. This ceramic’s crystals are needle-like, so when they are compressed they line up very tightly. This results in a much stronger restoration. The flexural strength is in the 360-400 MPa range, with a 70% crystalline structure composition. Again, the tight crystal alignment makes the material resilient to crack propagation, and the material’s edge-strength is extremely high. The material remains stable even after several firings, which means adding contacts or staining is not an issue.

As with the leucite material, the lithium disilicate ingots and blanks come in a full range of shades and opacities. Esthetic core cut-backs and layering also can be done with this material, and here a powdered fluorapatite ceramic is used.

Here’s a breakdown of each material’s flexural strength and crystalline structure:

Feldspathic porcelain
	Flexural strength: 90 MPa
	Crystalline structure: 20%

Leucite-reinforced ceramics
	Flexural strength: 140 MPa
	Crystalline structure: 40%

Lithium disilicate
	Flexural strength: 360-400 MPa
	Crystalline structure: 70%

The ingot options are an important feature in the pressed and milled materials. Again, we are trying to replace enamel and allow light to flow into the dentin and through the tooth. While a translucent shade may seem optimal, sometimes the more translucent shades inherently have a lower value. And of course there are times when we need more opacity to block a darker underlying dentin shade, whether it’s a result of tetracycline staining, a dark endodontically-treated tooth, or, as we see more and more, patients requesting “super” white bleach shades. In this case, more opaque cores not only block underlying tooth color, but offer a higher value. In any case, lab communication is very important, and it is especially important to communicate the “stump shade” of the tooth you’re restoring.

With today’s materials there is no reason we cannot meet our patients’ esthetic desires and our own requirements for longevity in our restorations. Education is key to making this happen. There are excellent continuing education opportunities available for today’s dentist to learn more about cosmetic dentistry. Dental schools typically do not focus on this highly demanded area, making post-graduate courses a must. Proper knowledge of the materials and techniques, and selecting a skilled laboratory technician, are vital to successful veneer cases. And with the advances in material technology, success is that much more attainable.

Dr. Lisa Kalfas is a 1987 graduate of the University of Colorado School of Dentistry and has completed several post-doctoral programs in cosmetic dentistry at the Las Vegas Institute for Advanced Dental Studies. She joined the faculty in 1999 and teaches post-doctoral courses in cosmetic and advanced dentistry. Dr. Kalfas has practiced in Boulder, Colo. since 1989 and is a member of several dental associations.

		Click here for slideshow of products that can help you achieve veneer success.

Articles

How to trim and shape bis-acryl provisional restorations

May 2010 | Dental Products Report
	Clinical 360°: provisional technique

		Strength and esthetics are the most important considerations when choosing a veneering material.

		The right material, good communication and the proper education are key to successful outcomes.

How to: Trim and Shape Bis-Acryl Provisional Restorations 

With the right tools at hand you can cut down the time required to prepare provisional restorations.

May 2010 | Dental Products Report Clinical 360°: provisional technique The take-aways   Strength and esthetics are the most important considerations when choosing a veneering material.  The right material, good communication and the proper education are key to successful outcomes.  How to: Trim and Shape Bis-Acryl Provisional Restorations  With the right tools at hand you can cut down the time required to prepare provisional restorations.

How to: Trim and Shape Bis-Acryl Provisional Restorations

	You are not the only ones wrestling with this daunting task! The issue of finding comfort in the “asking” always reminds me of a Theatre 101 class I took years ago. The first rule of the stage is, before you utter one line of dialogue you have to ask yourself,

	“What’s my motivation?” Your answer will color the tone, pace and delivery of that one line.

	The same rule applies to asking for referrals. If your motives for asking are based on desperation and scarcity, your dialogue will personify that. If your motives are based on confidence and passion in your practice, that will also change your dialogue. So before you and your teammates make any attempts at inspiring patients to refer, make sure you brainstorm your unified motives and purpose for wanting to invite new patients into your practice. Taking that one step will increase comfort with the process immediately.

Now that you have a unified purpose for “asking”, here are some helpful hints.

 Only ask patients who you like, and those who personify your vision and values of care.  The saying goes, “Eagles refer eagles.  Therefore if you ask a pigeon, he will refer another pigeon.

 Wait for a compliment… then ask! Studies have shown that if a patient has had an experience that has exceeded expectations, he or she is naturally going to tell 25 other people about the experience.  So ride the positive wave.

 Follow this model and you won’t sound like a salesperson.

	Patient compliment: “I love your team.  They are so warm and friendly!”

 Acknowledge the compliment: “Thank you!”

. Quality Statement: “It’s part of our vision to provide exceptional experiences to patients like you who appreciate the extra mile!”

 Transition Statement: “You know, not all patients get to experience an ideal dental environment.”

Ask: “If you have any friends or family members who would appreciate the same warm experience, please recommend them to us. We would love to fill our practice with patients just like you.” 

Amy Morgan is CEO of the Pride Institute. With Pride since 1993, she is a sought-after educator who still consults one-on-one with practices.

 You are not the only ones wrestling with this daunting task! The issue of finding comfort in the “asking” always reminds me of a Theatre 101 class I took years ago. The first rule of the stage is, before you utter one line of dialogue you have to ask yourself,  “What’s my motivation?” Your answer will color the tone, pace and delivery of that one line.

Ask Amy: Patient referrals

01 You’ve been in the dental industry for some time. What in your background prepares you for this role?

	I have recently taken full responsibility for Danaher’s worldwide imaging businesses, after more than 20 years in leadership roles running dental and imaging companies in North America and Europe. I was the President of Soredex (1989-1993) and  the President of Gendex (1993-1999). Between 1999 and 2007 I was Senior Vice President at DENTSPLY International, and from 2007 onwards, CEO of Instrumentarium and Soredex.

02 The group includes DEXIS, Gendex and i-CAT. With the acquisition of Instrumentarium and Soredex you are now leading the world’s largest dental imaging group. Will there be any major changes?  
	

	All our businesses are well positioned and we will continue to serve the dental community with all of our existing highly recognized brands, be distributed through our existing dealer partners, and supported by our existing sales organizations.

03 Last year was financially challenging for many companies. How did your group finish 2009?   
	

	The launch of the all-new DEXIS Platinum digital x-ray sensor exceeded all our expectations. We grew double digits last year. The introduction of the Gendex 8500 yielded a huge adoption rate and Soredex and Instrumentarium had a terrific finish to 2009. Based on recent DTA market data, Instrumentarium/Soredex was the market leader in digital pans in Q4 of 2009.  

04 What new product launches will we see this year?
	

	We just launched the GXCB-500 HD. It’s a new 2-in-1 unit that combines 3D imaging and traditional high-end panoramics - and all in High Definition image quality. We are also launching a new version of the highly popular Soredex Optime phosphor plate scanner and an Instrumentarium entry level digital panoramic unit.

05 How do you see your 3D portfolio expanding?
	

	We are pleased to see an exponential growth of interest in 3D and in our products. There’s no doubt that 3D is a hot technology. We’re well positioned with the i-CAT in the specialty market, especially orthodontists and oral surgeons, and with the Gendex CB-500 line supporting general practitioners, periodontists and endodontists. On the Soredex side we continue to gain momentum with Scanora 3D.  

06 How is 3D changing the way dentists deliver patient care?
	

	You don’t know what you don’t know until you have seen it in 3D. Cone beam CT technology allows dentists the most comprehensive view into the patient’s anatomy. As a result, 3D allows for better planning, a more predictable treatment and a safer procedure for the patient.

07 What trends do you see for dental imaging and how are your companies staying current?

	There’s a real demand for integration applications between cone beam and digital impression, restoration and CAD/CAM software. We’re excited that our cone beam systems offer an open software architecture that allows doctors to take advantage of these applications so they, in turn, can achieve more precise, reliable restorative and surgical results.

08 Many dentists are reluctant to make such big investments with the economy still in recovery. What is your  message to these doctors?
	

	Dentists shouldn’t hesitate to move from film to digital for 2D-it’s a given. Especially with intraoral, digital radiography has been proven to be more diagnostic, more efficient and more economical than film.

09 What about 3D, for those who may be intimidated by the initial investment amount?
	

	We actually see 2010 as “The Year of 3D.” The numerous clinical benefits speak for themselves. And with Section 179 deduction sharply dropping from $250,000 this year to only $25,000 next year, now is the best time to invest in 3D.

10 What is your vision for these companies and the imaging group as a whole?

	Combined, we offer more than 225 years experience in serving the global dental community. We are trusted names that have strong brand loyalty because of our dedication to quality and service. One common factor in the success of our companies is that they focus on the dentist first, and design and deliver products that improve their clinical lives.

 01 You’ve been in the dental industry for some time. What in your background prepares you for this role?

10 questions: Henrik Roos, President, Worldwide Imaging Group - Danaher

“Dr. McFarlane shows us the significance of having the end in mind by uprighting roots of teeth mesial and distal to a missing maxillary left lateral incisor. Often, when one case is given to five dentists, there is a good possibility that there will be five different destinations in mind. If ideal implant placement is the goal, uprighting of the roots orthodontically can benefit the restorative aspect of a case as well as the patient and patient’s overall smile.”
	-

	Although I have been an orthodontist since 1992, I have tried to keep up with advances in all disciplines of dentistry, especially through my interactions with the general dentists I teach, and as an enthusiastic member of my local chapter of the Seattle Study Group.

	Dentistry has made amazing strides over the last 20 years, as has orthodontics. I am here to convince you that with the addition of an orthodontic segment to your overall prosthetic treatment plan can take it from good to great.

	Some effective, relatable language for explaining this concept to patients is: “We’re going to get you some new tires, but you really need an alignment first.”
	Prime examples of this need are correcting deep bites prior to placing anterior tooth replacements, correcting CR/CO slides prior to placing prosthetics into a stable environment, and establishing correct spacing of neighboring teeth for bridges and implants.

	Orthodontics also can help you with crown lengthening, gingival margin height equalization, and bone level development for high quality prosthetic replacements. Many times, the case would be okay or so-so without some orthodontics first, but would be outstanding with some ortho in the plan.

	The orthodontic techniques used for a particular case vary widely, according to the complexity of the correction required prior to the prosthetics. Examples include:

	A removable device to close a central diastema prior to replacing a lateral incisor.

	Clear aligners to unravel some crowding or close extra spaces for more ideal prosthetics.

	Localized fixed orthodontics to emerge a hopeless tooth, thus leaving behind a more ideal bony site for implant placement.

	Limited fixed orthodontics to upright molars that have tipped into an extraction space.

	More comprehensive fixed orthodontics to level a deep bite, close an open-bite, or correct a transverse or A-P discrepancy-all in the interests of better prosthetic preparation.

	Comprehensive orthodontics with the incorporation of TADs (temporary anchorage devices) for pre-prosthetic solutions limited only by your imagination.

	Comprehensive orthodontics including orthognathic surgery to improve jaw relationships prior to tooth replacements.

	The case example that follows is a 21-year-old female who had a congenitally missing maxillary left lateral incisor, #10. The missing tooth had been temporarily replaced with a resin bonded bridge, as it was clear there was insufficient space at the gingival and, even more so, at the apical level for even the smallest of implants (

). Fixed orthodontic appliances were placed only in the  maxillary arch because the patient was not interested in having additional appliances in the mandibular one. NOTE: The exaggerated bracket placement on the left central incisor and canine was placed to produce root divergence away from the implant site (

	After 12 months of braces, including a bracketed pontic and some open coil spring for extra space (

), the patient was debonded and given a Hawley retainer with a prosthetic tooth (

	The implant dentistry was performed by Dr. Terry Koltek in Winnipeg. 

	In this case, the inclusion of orthodontics allowed a new option (implant replacement) into the realm of possibility, and allowed the dentist to take this case from so-so to so-great! The patient is thrilled.

	The pre-prosthetic orthodontics could be provided by the dentist, or as a collaborative effort between the dentist and orthodontist. Either way, communication is vital, both to convince the patient of the high value of adding orthodontics to the plan, and between practitioners to ensure the best advantage is created for the final prosthesis.

	The big winner is the patient, whose prosthetic result will go from good to great. 

R. Bruce McFarlane, DMD, BScD, MClD, FRCD(C), has a large specialty orthodontic practice in Winnipeg, Canada and, through his education company, ICANDO orthodontics, lectures extensively to dentists who wish to incorporate orthodontics into their practices. He also mentors dentists over the Internet on a case by case basis. Please visit  

Dental Products Report-2010-05-01

How to trim and shape bis-acryl provisional restorations

How to: Trim and Shape Bis-Acryl Provisional Restorations

Ask Amy: Patient referrals

10 questions: Henrik Roos, President, Worldwide Imaging Group - Danaher

A complementary approach