Mission: the purpose of this website

The purpose of this website is to provide follow-through support for course attendees and for members Dr Walford's Composite Study Clubs. The aim is to promote safe integration of new procedures into clinical practice for participants.

In developing this website, my goal has been to integrate both subjective and objective factors in the restorative landscape, and fuse them into to a sensible, intellectually clean and accessible system with defensible and defined choices.

All information and procedures on this site should be used entirely at the discretion and professional judgment of the users. Although data has been obtained from reputable sources and verified to the extent possible, there is always a possibility of error or misinformation.

This website is constantly developing and as such is a work in progress. Both critique and compliments assist its advancement. Please contact Dr. Walford if you wish to comment at pwalford@telus.net.

To access pages that describe the overall mission and direction of the study club program, click on this link The New Paradigm of Composite Resin

Procedures and Scope of this Website

This website was initiated in 2007 to develop and share information and clinical expertise in areas of adhesion dentistry which are under-studied in the profession today, yet form a sizable part of the general practitioner's daily workload. This website aims to reduce that deficit.

These include:
  1. Posterior single surface direct composite restorations: Class I, PRR,Sealant,and Class V See Preventive Resin Restoration See Class V Restorations
  2. Multiple surface direct posterior composite restorations: Class II, Class II with shoed cusp, cosmetic cusp replacement i.e.,MODB,and complex multi-surface restorations, i.e.,MODBL. See MODXYZ, MODB Class II?
  3. Anterior attrition restoration with composite resin, with associated buccal and lingual shoes See Incisal Attrition
  4. Incisal augmentation to increase vertical dimension, using composite resin. See Extreme Resin Makeovers
  5. Adhesive Prosthodontics, including Anterior Inlay Maryland Bridges see Inlay Adhesive Bridges, and Posterior, Yamashita-type bridges,see Adhesion Bridges and their associated impression and temporization procedures.
  6. Adhesive protocols for post placement, core buildup, crown repair, porcelain and alloy bonded procedures, see Vital Core Buildups, Posts and Cores, Adhesive Cementation, Recementing of Lost Crowns

Material not found on this site

Restorative procedures that are widely studied and well-taught today are excluded:
  1. Conventional anterior composite preparation and restoration
  2. Porcelain laminate veneers
  3. Metal-free crowns and inlays
  4. Implants

Information sources and motivation for this website

Composite dentistry, as a field, belongs to the general practitioner, and is a complex patchwork of information, products,resins,devices,curing lights, manufacturer's claims,historical customs and clinical experience. After the past 20 tumultuous years of development, it would be unlikely that any two dental offices anywhere perform routine composite procedures in exactly the same way. While it can be assumed that each practitioner does his or her best, the definitive textbook of restorative procedures has yet to be written.

Technique seldom meets all the desired criteria of evidence-based practice, although the microscopic scale of adhesive dentistry demands it.

General dentists assemble their technique from a variety of sources. Some choices are inspired by apprenticeship and mentoring, as young practitioners interact with seasoned professionals.

Other methods and choices in the profession are based on real facts, for example, published flexural strength and other measurable parameters of composite resins.

Others are influenced by articles, journals, and other publications of variable credibility. Some practitioners base their choices on experience,others are based on trial and error.

A practitioner's technique is therefore a human thing, assembled in a non-linear way from a polyglot of sources.

In developing this website, my goal has been to integrate both subjective and objective factors in the restorative landscape, and fuse them into to a sensible, intellectually clean and accessible system with defensible and defined choices.

I have had the benefit of serving a progressive,stable patient group on two small islands in the Straits of Georgia, 100 miles north of Vancouver, B.C., for 30 years. In the 1990s my patients were refusing amalgam due to fears of mercury, and out of this stalemate was born the challenge of placing resin restorations of all sizes.

Thus I was pushed aboard the composite boat early in the 1990s, after Generation IV bonding agents were developed, and hence I have had 30 years in the same location to see what works with resins and what doesn't. What began as a response to my patients' flight from amalgam, has evolved into a quest for excellence, longevity, rationality and powerful therapeutic expertise in resin restoration.

As I enter my late sixties, family grown, I have time to contribute to the profession, and assemble the whole of this hard-won expertise into a format accessible to others.

In the field of resin restoration, misinformation abounds, thanks to an insufficiently regulated commercial sector attempting to increase market share at all times. Thanks also to a regulatory structure that relies on previously similar products to certify new product formulations, so that individual new products may not be sufficiently vetted.
As well, tests to establish long term performance and degradation are sadly lacking in many areas. Regrettably,acceptable and realistic tests for biocompatibility of these intricately diverse formulations are also not widely performed.see Biocompatibility for some interesting research in this area.

The field of composite dentistry today

Today we face a clinical need to fuse an enormous array of products to an equally wide spectrum of patient needs. We are in an era in which there is tremendous intellectual and moral stress within the profession in the area of composite resin. Regrettably, these conditions piggyback on an economic climate in which practitioner debts for education and practice acquisition are spiralling upward. The need to generate production overlays a field with insufficient scientific grounding. Standard of care is virtually impossible to define - even university-based teaching does not agree from faculty to faculty.

The field is amazingly broad, complex, and internally inconsistent. One reason for this is lies with the over-development of products. There are simply too many products. The cost of research prohibits all but major players from completing longitudinal studies, so product certification is based on likely expectations- not proven clinical performance!

A second intrinsic problem is the invisible nature of many key factors, including bond strength, polymerization contraction, and cure. When something goes wrong, how do we interpret the result if the controlling factors are invisible? Consequently, many clinical shortfalls, seen first-hand, do not explain themselves readily, leaving us guessing as we try to "reverse engineer" a problem.

The classic human response to invisible control has been fervent belief and superstition. Phlogiston, phases of the Moon, humors of the blood... the history of science abounds with examples of illogical and mystical response to the unknown. Dentistry is not without this element of fervor, faith and catechism. But the will of the human mind is to know, and the overall thread of science and technology has been to explain events reproducibly.

So this website is an exploration, voluntarily undertaken, spurred by a need to know, a desire to excel,and belief in the power of collaboration in advancing the profession. As a creative act, it is also my personal PhD thesis,if you like,well,"Just Because".

The proper place of "Evidence-based Dentistry"

Innovation and evidence occupy opposite poles of a spectrum. The quest for certainty has very little to do with the desire to try something new.

In dentistry, the buzz-word "evidence-based" has gained credence as the proper basis for clinical procedures.I would prefer that it be so. Academia clings to this phrase as a firewall behind which to claim legitimacy of leadership. Nothing could be further from the truth. Academia does not occupy the leading edge of dental technique, but rather the trailing edge. By the time a procedure finds its way into curriculum, it is so old and stale it is almost obsolete. It is, however, probably exhaustively researched. All the parameters are known, the science is sound, it is safe for newly trained dentists to undertake on patients. It is just 30 years out of date, limiting, static.

This legacy position of academia in a fast-moving profession saddles the new graduate with the daunting task of entering the on-ramp of a world of clinical practice and trying to get up to speed of the informational traffic. A further handicap imposed by the "evidence-based" catechism is that it numbs the intellectual and emotional capacities for curiosity and original thought on the part of practicing dentists.

As an assumption it presupposes that no individual can take action unless someone else has already tried it, researched it, and published on the subject. It presupposes that all techniques are already fully known and deployed. A further sequel to this mindset is that nobody has the capacity to inquire, reason, or solve problems arising from their experience. Perhaps we aren't even credited with experience: perhaps we are all automatons waiting for direction from a higher authority.

I reject this worldview as stifling of professional progress. However, in dentistry there is an inviolate need to protect the patient from unsound applications, and this website is founded in that requirement; the need for a factual basis and explicit reasoning for our regimens, old and new, but particularly, the new.

However, conventional treatment sometimes offers a patient no solutions,i.e., we are at a dead-end.Bring out the forceps.
In my view, it seems reasonable with patient consent to attempt rational extrapolation to a new mode if the expectation is that no harm will come of it. My clinical problem-solving in the face of dilemmas at the end of the known dental universe has been to develop solutions that now are a platform for reliable routine care far beyond normal limitations. I do these procedures every day, and have case experience sometimesexceeding 3000 placments. I do my resin dentistry in at least 100 ways different from the mainstream, in the way that I achieve isolation, hemostasis, preparation design, placement, matrixing, finishing and polishing and articulation. Most of these clinical solutions are just a small step or two away from what has already been known, proven, manufactured and sold already. Sometimes these small steps are game-changers, utterly changing the experiece of the practitioner and the outcome of the tretament. Nonetheless, how do I support these innovations?

Getting real facts

The materials side of composite resin is difficult; facts may be unavailable, skewed by manufacturer's self-interest, or simply incomplete. Take one simple parameter, one that is critical to marginal ridge fracture resistance: Flexural Strength. The flexural strength of resins is seldom found in the fact sheet accompanying syringes or compules of resin; to find that information, the practitioner must expend extra effort, perhaps writing the manufacturer, or consulting the journals that have laboratory research or clinical trials at their disposal.

In advertising, the manufacturer may claim their resin is "strong" while, numerically, its flexural strength is actually in the bottom quartile. Flexural strength may vary even within the shade range of the same resin: for example, in some resin systems, translucent and bleach shades show lower flexural strength than body and dentin shades, due to different photointiators, particle formulation and filler loading.

To complicate matter further, within Flexural Strength as a parameter, there are two tests in current use under ISO 4049; a three-point test and a four-point test. To understand the facts and figures, one has to know which test is being used, and know which one best predicts clinical performance. Consensual answers to this series of questions do not widely occupy our professional dialogue.

Further difficulties conspiring to block mastery can be found in adhesives: while immediate adhesion is measurable, there is not a recognized accelerated aging test for adhesion; some manufacturers perform thermocycling tests, of up to 6 years' duration to determine long-term performance, but clearly the mouth undergoes more than thermocycling effects and six years is less than our desired clinical lifespan.

The mouth is a biotic zone with acidity changes, numerous complex chemical assaults, and is co-factored by exposure to cyclic structural loads. There are numerous papers showing that some adhesive bonds degrade rapidly due to hydrolysis, "water trees" (transudation effects) or even phase separation in the bottle before adhesives actually even reachthe tooth. How do we practice excellent dentistry alongside these sort of observations?

So even in basic facts - the flexural strength of a resin, and its long-term adhesion to a tooth, one wanders off the "evidence-based" trail and begins groping in the dark. We still have to perform restorative dentistry and stand behind it.

Appropriate theoretical models

To complicate matters even further, even with correct facts, the conceptual basis for the use of facts may be incorrect. For example, polymerization contraction was once thought to be predictive of contraction stress to the tooth. Many resins were sold on the basis of their low contraction percentage. This widely accepted idea has been superceded by a more complex concept of stress; varying as a multiplier of flexural modulus, ie bifactorial, and also as a time-related event, i.e., stress rate. Now contraction stress is now being measured through this lens and it is found that this model is only partially predicative, and the real story is still elusive and more multifactorial.

Resin curing is another area where the current theoretical models are not appropriate. While many curing lights continue to be sold by manufacturers on the basis of Milliwatt output at the light tip, the critical concept is the amount of light received by the resin in the preparation in joules.

Most practitioners do not know that curing light intensity falls off as the third to the fourth power of the distance from the resin.(Price 2006, see Curing Composites Curing lights of equivalent initial output at the tip are often radically different at the usual clinical distances from the tip. Even when output degradation is known, output alone does not correlate perfectly with cure. It co-factors with wavelength. Within the broad family of resins, there are three different photo initiators currently which match to a greater or lesser extent with the wavelength emitted by a given light. Some shades within a resin range may be extremely hard to cure, even in shades as light as A3, due to photoinitiator/light output mismatch.

As clinicians, we do not have any real way of knowing if all the components in this complex system-light intensity-light decay-photoinitiator-shade-distance are producing a photoconversion that is close to ideal. 40% cure and 80% cure look the same clinically - both are hard to the touch and hard when cut with rotary instruments. They behave utterly differently in terms of longevity, stain resistance, fracture resistance, marginal chipping, water absorption and release of uncured monomer.

There is no scientific way for clinicians to validate clinical cure even at the outset with new equipment. We end up guessing on the basis of how well we have understood the basic components of the photo-curing world. It is at best,inferential, at worst, conjectural.

Compare this to the certainty with which one can ascertain proper function of one's autoclave, through independently verified spore tests. Would it not be a valuable addition to the profession if one could send office-cured resin samples to an independent lab and have a percent-of-cure reading returned in a few days?

In conclusion: Excellence Today - a Flawed Universe.

Delivering 100% "Evidence-Based" treatment in this present professional reality is impossible. Instead we must make best guesses in what amounts to a boiling pot of facts, commercial factoids, incorrect concepts, and inappropriate or simply unavailable testing.

Where does clinical experience fit?

40 years of dental practice may represent 40 years of progress, or one year of progress repeated 40 times.

Not all practitioners have the capacity, time, interest or skills to advance themselves as much as they would like. They must rely upon the others in the profession to spur advancement. These leaders are the progressive, innovative, and creative individuals with favorable circumstances who foster advancements. I assert that every person who rejects the norm and develops new therapies must at least temporarily leave behind the comfort of "evidence-based" treatment and extrapolate into what isprobable clinical success.

If not, we would never have the innovations that have entered the profession every year. Since my graduation from McGill? in 1975, just to skim the surface....

  • porcelain laminate veneers
  • tooth bleaching
  • rotary endodontics
  • implantology
  • bone grafting
  • soft tissue grafting
  • laser-cautery
  • laser-assisted periodontal therapy
  • MTA endodontic procedures
  • etc...

These procedures that were unheard of two decades ago now have gained substantive evidence of success, in fact, have become normal standard of care since their early pioneering stage, and are fully-fleshed out in the marketplace and in the CE world.

Experienced practitioners know that we repeatedly face clinical challenges which have no stock answer, even,for example, as simple a challenge as restoring an extensively or seemingly impossibly decayed tooth for a patient who cannot afford crown work, using composite resin.

The desire to help this patient and attempt treatment rather than extract the tooth motivates us to innovate. We grapple with the situation, using what was learned from the last time a similar condition was encountered, and go beyond it. The better we do it, the longer the service life. Study clubs are a powerful context for this forward compounding of clinical expertise. This is why I strongly believe in the need for study clubs to break down the limitations of solo practice and to collectivize our experience.

Over time, stepping stones appear from the mists of the unknown, and track us to successful strategies at the edge of what was previously considered impossible. My study clubs, both being a mentor and a participant, are the genesis of these explorations and this website is the story of the journey.

The factual reports, tables, journal citations and so on on this website are to confer objectivity to the extent possible to the assertions made herein. At best, despite our aspirations to the contrary, dentistry remains a quasi-scientific field. The trail of evidence quickly becomes murky as one enters all aspects with a questioning mind.

Within the procedures covered on this website, if the theoretical model of a proposed technique differs from that of the mainstream, I have attempted to make my conceptual assumptions clear so that they may be clearly interpreted and hence, debated.

Basic references

My information sources include the following core references.

Summit and Robbins,Fundamentals of Operative Dentistry, Third Edition, Quintessence Publishing

This widely used university text is a warehouse of relevant references, histological data, and classic restorative axioms. However, it will not tell you what bur to pick up, how to develop good margins, which bonds are best, how to place resin, which resins are best for the application at hand, and how best to achieve a beautiful finish.

It is not a handbook of clinical procedures. After reading it cover to cover, you couldn't perform restorative dentistry with it. On the other hand, you can't perform excellent restorative dentistry without it.

My goal in using this text has been to seek an accountable thread from science to clinical technique in developing operative procedures.

One serious drawback of Summit and Robbins is that the personal bias and preferences of the authors are admixed, almost in the same breath as factual evidence. Expressed another way, factual evidence is frequently confounded with an author's preference. When they say something isn't indicated, that's an opinion, a preference, a bias, a consensus- a human thing. When they say that the depth of etch with 37% liquid phosphoric acid is 5.5 microns in 15 seconds- that's a fact - science.

It is unfortunate that this critical distinction is frequently blurry in this textbook. But that's the field of clinical dentistry - a process of quasi-scientific consensus that slowly moves forward in time.

The deficiencies of this textbook are a lack of data on product choices, scant visual representation of preparations and little committed illustration to the critical issue of how composite preparations need to differ from GV Black amalgam preparations.

As well, there are insufficient procedural guides, or algorithms for managing normal clinical contingencies. Perhaps this deficiency is intentional- deferred to the prerogative of Restorative Departments of dental schools the world over.

The Dental Advisor

See http://www.dentaladvisor.com/.externalexternal link link The Dental Advisor is a subscribed journal that evaluates clinical products. If you want a review 15-year performance of Z-250 composite resin, this is where you will find it. Past issues can be readily accessed online when one purchases the required subscription.

An annual report of preferred products is issued each December. It is a worthwhile guide in researching the best products in the field, and for taking the pulse of the dental industry.

Clinician's Report (Formerly CRA News)

See http://www.cliniciansreport.org/.externalexternal link link
Clinician's Report is also a subscription-based journal. Past issues can be readily accessed online when one purchases the required subscription. The search engine, after a badly needed upgrade, is still deficient.

The CR organization has been a shining light for over 20 years, forcing accountability upon the dental industry. CR is almost a dental school in its own right, with many outreach clinical teaching programs, and a hefty wing that performs research and clinical trials.

If you want to find the adhesive value of bonding agents, laboratory assessed, along with price per ml., and dozens of data points,this is where you will find it.

An annual buying guide is produced in December, highlighting worthwhile innovations in the field. While their search engine needs more improvement, accessing full back issues is easy. Thus I can always quote the specific issue when citing it.

Reality Research Labs

See http://www.realityesthetics.com/portal/external link

This organization performs independent, laboratory-based product research.It excels at corroborating findings indicated by other organizations, and has an effective search engine, and every two or three years produces a massive 1200-page text full of excellent product reviews..
Follow this link: http://www.realityesthetics.com/portal/external link

Online links

A number of sites have active chat rooms for professional dialogue, and these are always interesting and sometimes inspiring.

Website Reference Library__

A collation of other material can be found at References


I hope the reader will take full advantage of this "work in progress" to liven their imagination, raise unconscious assumptions to the forefront, debate openly, delve deeper into the controlling factors for success in adhesive dentistry, and come out the wiser. I have been rewarded by the appreciation and respect of hundreds of dentists over these past 13 years since rising to the commitment of being a teacher. I hope, before putting down the hammer entirely, to encapsulate this knowledge better using electronic formats that allow rapid access. I also hope to be part of that small cohort of the dental profession that don't mind the pain of leadership into a better tomorrow, and affect the shape and progress of our wonderful and difficult profession.

Peter Walford, Spring 2017