Which technique(s) should we use to fill a Class II proximal box? Is there a difference in the long term margin integrity?
This question was submitted by a general dentist:
I always worry that the cavosurface margins of class II preps are not fully filled when using composite resin. Is there a difference in the long-term margin integrity using the following 3 methods?
- Pack composite resin into the proximal box using an amalgam condenser.
- Place flowable resin along all cavosurface margins of the proximal box and cure it prior to packing composite.
- Place flowable resin on the cavosurface margins and then insert composite on top of the uncured flowable.
Dr. John Burgess and Dr Suham Alexander provided this initial response.
Dr. John Burgess is Professor and Assistant Dean for Clinical Research in the Department of Clinical and Community Sciences at the University of Alabama’s School of Dentistry
Current reviews of the literature demonstrate that the annual failure rate of posterior composite resin restorations range from 1-3% per year. (1) Although some clinicians use bulk-fill techniques to fill composite resin restorations, the most common technique employed is incremental fill. Often dentists are concerned about gingival marginal integrity in the proximal box area. Common reasons for marginal leakage are poor adhesive placement or composite resin lifting during placement when the resin material adheres to the packing instrument. This effect can be minimized by lubricating the condenser with bonding agent or alcohol which does not weaken the resin unless a significant amount of the bonding agent is used. (2) Clean instruments, free of debris and scratches, prevent the resin from sticking to the condenser. Flowable composite resins round sharp line angles produced during cavity preparation and were supposed to improve marginal adaptation of posterior composites by stretching and acting as a stress breaker. However, a two year clinical trial reported no difference in marginal integrity or success of two types of composite resin restorations lined and not lined with a flowable material. (3)
Various techniques have been used for class II composite resin restorations:
Snowplow
In this technique, flowable composite resin is placed in the proximal box and composite resin is packed on top of the flowable and then cured. The depth of cure in this technique may be hindered especially if the initial increment of flowable and the composite is greater than 2mm. In this case, light penetration through the combination is poor, the bond is weakened and increased marginal leakage may occur. Currently, the author cannot find any clinical studies related to this technique.
Open Sandwich
This technique is used in high caries-risk individuals where a resin-modified glass ionomer (Fuji II LC) or densely-filled GI (e.g. Fuji IX) is used to fill the proximal box to the level of the pulpal floor. (4)Note that a glass ionomer restorative material is used, not a base material which produces increased fractures in the restoration compared to the restorative material. (1, 6) The fluoride release around the margins of the proximal box protects approximately 3 mm around the restoration which helps protect against recurrent gingival caries.
Flowable as The Initial Increment
In other situations, flowable composite can be used in the box to fill undercut areas of a tooth preparation and be cured as the first increment. The rest of the box would be filled with the regular composite resin material. No clinical studies could be found that illustrate that the use of flowable composite offers an advantage to the final restoration. Flowable resins adapt well to angular and rough cavity preparations and no disadvantage to its use could be discovered.
Practically, solutions to these types of problems include using a small amount of flowable as a liner, placing a resin modified glass ionomer in an open sandwich technique for high caries risk patients or alternatively, using a moderately condensable composite and carefully condensing it with new clean condensers.
References
- Demarco FF, Corrêa MB, Cenci MS, Moraes RR, Opdam NJ. Longevity of posterior composite restorations: Not only a matter of materials. Dent Mater 2 8 (2012) 87–101.
- Perdigăo J, Gomes G. Effect of instrument lubricant on the cohesive strength of a hybrid resin composite. Quintessence Int. 2006 Sep;37(8):621-5.
- Efes BG, Gomec Y, Koray F. Two-year Clinical evaluation of omocer and nanofil composite with and without a flowable liner. J Adhes Dent 2006 Apr;8(2):119-26.
- Andersson-Wenckert IE, van Dijken JW, Kieri C. Durability of extensive Class II open-sandwich restorations with a resin-modified glass ionomer cement after 6 years. Am J Dent 2004;17:43–50.
- Opdam NJ, Bronkhorst EM, Roeters JM, Loomans BA. Longevity and reasons for failure of sandwich and total-etch posterior composite restorations. J Adhes Dent 2007;9:469-75.
- Gaengler P, Hoyer I, Montag R. Clinical evaluation of posterior composite restorations: The 10-year report. J Adhes Dent 2001;3:185–94.
I have been using composite for nearly 30 years and have observed the wear and tear of many composite restorations during this time. Many were placed on dentin gingival tooth structure and have stood the test of time very well. Never bought into using flowable since it shrinks 4% whereas my microhybrid shrinks 1.7%. Microhybrids flow easier than the newer nanofills and nanohybrids and are stronger so I have not gone to these composites for posterior restorations. I also fill the gingival box 2mm and cure and then wedge my tooth. Wedging the first increment will sometimes cause the matrix to move into the box so I cure the first 2mm and then wedge and then add the rest of my mesial or distal wall in one piece. I also fill the rest of the tooth using a technique similar to placing styroform cups together in a sleeve of cups. I feel this reduces the contraction shrinkage between the cusps and allows the shrinkage to move towards the existing composite. Has worked well as my restorations are lasting and most new caries is due to poor hygiene. I have many 25-30 year old composite restorations that are working well. Just my 2 cents.
Studies carried out by David Clark have shown that voids form at the interface between the cavosurface margin and composite ,within the composite between increments.
This is a fault in the filling technique another major disadvantage is the inherent polymerization shrinkage that comes with placing composite.
The techniques to minimize this are
Magnification – powerful aid in removal of caries beyond CEJ
adaptation of matrix band and wedge to seal gingival seat
Minimally invasive prep – David Clarks cavity prep which is a modification
of a slot with bevelled margins to infinity
– This allows for placement of minimal amount of
resin with minimal shrinkage which reduces
the c factor
Placement of composite – Clark emphasized that we place composite on the
tooth rather than in it. we cannot apply physical
pressure due to its thixotropic nature rather it
should be massaged over the surface.
Clarks technique involves curing of flowable and paste composite together rather than as separate increments
References
the injection molded technique for strong esthetic class ii restorations
Introducing the Clark Class II Restoration
No matter what technique you swear by, they all will not hold a candle to amalgam. Sorry, try as you may and I have after 35 years of practice, composite resin contacts are hit and miss. It is not possible to compact resin firmly against all surfaces with any degree predictability. Those that claim so are less than truthful or delusional or not looking close enough. And finally, just use composite because the fee is higher.
Period End and I do not care what any rebuttal is presented. You can not fool an old GP.
Paul
Right On, Brother. What don’t young dentists get about filling a hole with acrylic that shrinks 2 to 4 per cent
David Lipnowski DDS 76
You are correct!I am an endodontist,and composite restorations are my bread and butter.
Most of them fail at the proximal box from undercuring,of under packing.
There are lots of sixty year old alloys out there.Composits have not even been around that long.
The chief benefactors of composite restoration are those who manufacture and sell the product.
I was a big fan of amalgam for many years, but once I started using a sandwich technique with true glass ionomer (fuji ix GP Extra) and sectional matrices with separating rings (v-ring or garrison type), contacts are always great. If I can’t place a sectional matrix I use a regular one with holder and also apply separating ring. I rarely use amalgam now. I find in moderate to high caries risk individuals these last longer than amalgam (sandwich technique is hard with amalgam as it tends to crush the GI). Cost is not a factor, amalgams are much faster to place than composites and one can make more money doing them. Not knowing right technique to place them is no excuse for saying they don’t work. I like amalgam and it is a great restorative. I would not take it out for the sake of cosmetics or because patients think it is toxic. I have seen tons of cracked amalgam teeth and very few composite (and I have been doing them both for over 20 years). Done properly to minimize shrinkage and dehydration, composites are a good alternative to amalgam that don’t have to kill pulps, cause sensitivity and be prone to secondary decay. They take longer, you need a good curing light and they can be a pain in the butt to place but I get great success with them.
I agree with Dr. Belzycki, although I’m just baby with 32 years of practice!! Having said that, there are times when we do posterior composites. If the proximal box ends on the root, I’d prefer amalgam, however if I am doing a comp, then I usually put a flowable in first.
I’m surprised to hear the 1-3% failure rate. One of the composite manufacturers recently printed some literature showing an 8% failure rate–and that is in their own literature!!
I wonder if the restorations in the studies that look at the longevity of composite restorations were placed under rubber dam.
I am a new grad, working for 3 months, so unfortunately I do not have the test of time to see my restorations longevity yet. Throughout school I have used amalgam, composite and RMGIC/GIC. I have talked to many dentists listening to their points of view and gathering tips and tricks from them.
To claim that composite restorations fail way more than the literature suggests or that you can’t reliably produce contacts means that you are not working with that material correctly. I have placed around a few hundred class 2 composites and only 2 of them did I not like their contacts. One had no contact so I quickly removed part of the box, put the matrix back in along with a larger wedge, burnished the matrix band, re-etched then filled it to get an ideal contact. Note: we were taught that you can add composite to composite within 2 weeks of initial placement to get polymerization between the molecules. The other time I was unhappy it was a light contact between some rotated teeth in a tough clinical situation so I let the patient know and they were okay with paying extra attention to cleaning that area.
The key to composite is isolation like someone else mentioned. Whether it is by rubber dam or cotton rolls. I believe that the most important part is to get a great matrix adaptation sealing off the cavosurface margins. Using a wedge and burnishing to ensure good contacts. And where possible using a bitine ring. The key to handling composite like one of the ways the authors stated is to massage the composite into place. I usually use a condenser as well to gently pack the box which has a tight seal from the matrix if placed correctly.
Now for the discussion on amalgam. I personally hate massive preps and needing undercuts which weaken the tooth. I would much rather use bonding than mechanical retention. We were even taught to make slightly divergent preps so any failed composites fall out rather than hiding recurrent decay. Also the fact that amalgam creeps over time especially if it was not isolated properly during placement. I feel like many amalgams cause teeth to Crack and have heard this from many dentists 3 times my age. Lastly amalgam is very unesthetic. For these reasons I prefer not to use it.
I try to be fair to all materials and weigh their pros and cons. I am a huge supporter of gold inlays, onlays, crowns, and 7/8th or 3/4 crowns and personally find gold 100 times more pleasing to see in the mouth than amalgam even though I still admire a beautifully carved amalgam. Any time I have serious concerns about isolation I go to RMGIC or GIC which seems to be highly underutilized in North America. Usually I’ll use it for really sub G restos or DO’s on wisdom teeth, etc. Sometimes I’ll use it as the first layer in an open sandwich technique like the authors talk about – generally for class 3’s. I have also used a soft tissue laser before which works great for sub G restos.
Anyways I know this was a massive reply but I am passionate about quality dentistry and those are my opinions. Whether you agree or disagree. Whether you think I lack experience or have a newer, updated education, that is your opinion.
Three months, wow!
Amalgams cause teeth cracking only in our dreams, this is a ploy for early removal, no science to back up this fictitious claim. Wait a few years and you will see what ALL of us know, BPA composite is a poor substitute for Amalgam and far more toxic.
We say white on top black on the bottom, or KKK fillings white, but not very nice.
Ah, the exploding Amalgam theory, just medieval hype to get your amalgams replaced for profit, no real scientific evidence, used car salesman tactics.
BPA-based composites are far more toxic than amalgam and anyone with experience, if they are honest, will tell you they are grossly inadequate to fill posterior teeth with. They are temporaries in the posterior, plain and simple.
Wish we had a white alternative, we call composites KKK fillings, they are white, but not very nice. Gold is still the best, by a country mile, hopefully there is something in development without the Estrogenic side effects of Bis-GMA resin.
Would love a Cad/Cam hydroxyapatite block!
After almost 30 years in practice and having read a great deal of the literature, my observations are as follows:
– Well placed composites have the potential to provide many years of service, but in general they do not serve as long as amalgam
– There are clinical situations where composites will not perform as well (poor isolation, high caries risk, etc.) and an alternative is required. This is where amalgam has served me well as a cost effective, durable material with some clinical forgiveness.
– Mechanical retention is still required for composite restorations; simple reliance on dentin bonding alone is problematic because dentin bonds degrade over time (this is why porcelain veneers will fail when bonded exclusively to dentin).
– Gold is an excellent material, but unfortunately excellent skills for placement and additional cost is an impediment to its regular use.
– GI or RMGI also require excellent isolation.
– Thorough discussion should take place with the patient as to the materials available and the conversation must include the risks/benefits/costs of all of them; some patients will appreciate the advantages of amalgam (or gold) and will select it.
– For those who are new to the profession, keep in mind that everything is successful for a period of time, but it is with the benefit of time that we observe failure and can learn from it. Many clinical studies that are published tend to review restorations over relatively short periods (1, 3, 5 years); if my restorations last only 5 years, that is unacceptable.
-There are many materials to choose from, whether for restorative, endodontics, prosthodontics etc. each with their pros and cons and each with their applicability to certain circumstances. It’s helpful to have many tools in the toolbox; my strategy has been to select materials/techniques wisely, apply careful technique, encourage excellent maintenance, engage regular observation and refer to a colleague when you question your ability to deliver the optimum level of care.