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The Whys of Dentistry: Zen and the Art of Oral Care:  A medical management model of dental disease  Dr Kevin Scally

The graduating degree in dentistry is a Bachelor of Dental Surgery and the Surgical Management Model dominates dental care delivery: cut it out and bog it up (the drill, fill, and bill model) and the shake rattle and roll it out (the extraction and bill model).

Training based on the Medical Management Model would emphasise the etiology and cofactors of dental disease pathogenesis, and the surgical management of the disease would follow.

This model would not just concentrate on hard tissue and periodontal tissue disease, but also on mucosal, glandular, functional, and behavioral pathology of the oral cavity

While the clinical progress of the treatment may look the same, the intellectual underpinning of it by the clinician would be radically different.

With this in mind I would like to present some observation on current dental treatment and some suggestions on other methods of management.

Why amalgam?

This material has an impeccable historical pedigree. It is relatively technique insensitive, but it is time consuming. It is not a biomimic, it does not bond to tooth structure, and it doesnít release fluoride or protect the tooth from decay

As a material dental amalgam will continue to provide tremendous service to dentistry in spite of the increasing public concerns for its use. While it can be self sealing, and with the development of enamel bonding systems retention has been improved, it still has two disadvantages: its colour and its lack of effect in decreasing the incidence of caries other than reducing the microbiological load.

Why composite?

They adhere, they are technically demanding, and they donít prevent decay.

Micromechanical bonding through acid etching has been one of the greatest advances in dentistry this century. Its use in preventive dentistry as a fissure sealant has also been a breakthrough. Unfortunately, like amalgam, it has no impact on disease incidence in a caries active mouth, but it is the right color and has been actively promoted as the ultimate restorative especially in the USA. Its disadvantage is that it is technique sensitive and it requires meticulous dryness - a challenge to some patients and clinicians.

Why not glass ionomer cement?

In the management of dental caries the general approach is to debride the decalcified enamel and dentine and prosthetically replace it with an inert material: silicate (now abandoned), composite resins of various flavors, silver mercury amalgam; and, in another dental life, cast gold, porcelain, and hammered gold foil. In more recent years a new material has emerged, glass ionomer cement.

With the advent of this biomimic dental material there are emerging alternatives to "permanent restorations". This not so new material has been making inroads into conservative dentistry as an alternative prosthetic replacement material. This is the first of a new breed of dental restoratives that mimic biological dental composites: dentine and to a lesser extent enamel.

It has other advantages, it is the right color, it chemically bonds to enamel, dentine, and cementum: and epithelium glues itself to it.

In addition it releases fluoride, exchanges calcium phosphate with saliva, and recalcifies demineralised enamel and dentine. When mature it can be etched like enamel so that composite resin restorative materials can be bonded to it.

Its disadvantages: it looks so good it is difficult to determine if it has been used as a "temporary" restoration.

In high-risk groups the surgical management model for caries does not work. Teeth meticulously restored with inert prosthetic materials don't protect the tooth from further carious attack. It seems to me that the logical approach in the treatment of this group of patients is to use glass ionomer cements and once the caries is under control the restorations can be revised, occlusally and interproximally, with other more durable materials, be they composite resins or amalgam.

Whereas composite resin restorations have radically changed aesthetic dentistry, I believe that glass ionomer cements will be seen as the greatest advance in restorative dentistry and the first biomimic dental material. In a caries at-risk patient or in a caries active mouth it is the material of choice. It is the perfect intermediate material and it can be considered a permanent restorative in some situations.

Why cast and fired crowns?

Why not, acrylic crowns and composite crowns for anterior teeth and why not stainless steel crowns and preformed semiprecious crowns for posterior teeth?

In the caries challenged or badly broken-down dentition, these options can provide long-term interim restorations. Once disease control has been established, it is then possible to revise these prostheses with more aesthetic and durable restorations. This is an accepted practice in paediatric dentistry, so why not for selected adult dentitions?

Why AH26 and GP?

The corner stone to endodontics is to debride the pulpal contents and then obturate the space with biologically neutral or bacteriostatic filler sealed off from the oral cavity. It has been shown that just removing the necrotic pulpal contents and sealing the pulp chamber from the oral cavity is a sufficient interim treatment. So why not calcium hydroxide in the canal and have this sealed off from the oral as an intermediate therapy? With appropriate instruments this can be achieved in minutes rather than hours in conventional endodontics.

The current recommended treatment is to root-fill the tooth with gutter purcha and lateral condensation. The cost for this on a three-rooted molar is currently $300 to $500. Many financially challenged patients request extractions rather than this perceived expensive treatment option. It seems to me that intermediate root fillings should be on offer.

Why metal partial dentures?

Metal partial dentures are removable bridges. Their success depends on the longevity of the remaining dentition and the intelligence of their design. An alternative is a precision plastic partial denture. These have many advantages and are a rational alternative to expensive and clinically demanding metal partials. The prevailing attitude in dentistry is "This needs a bridge, canít afford it! Well a metal partial denture would be an option. Canít afford that either! Well I can make a gum-stripper plastic partial denture for you then". And an alginate impression goes off to the technician without instructions.

The concept that this is a second or third-rate treatment is wrong. The advantage of a precision plastic partial denture is the advantage it gives the patient. They can get used to the foreign body in their mouth, the prosthesis is easily modified, and, if made with the same undercut blocking out techniques used for metal partial dentures, they donít take forever to fit clinically. They are the treatment of choice in a hospital dental situation when the dentitionís future is in doubt. They are also very cost effective.

Why take out wisdom teeth?

Removal of wisdom teeth is considered by cultural anthropologists as a right of passage. There is increasing criticism leveled at their prophylactic removal. The culture of their removal has evolved into an expectation of late adolescence and mirrors the right of passage of teenage orthodontics. The evidence for their removal is just not there. It seems to me there should be an intervention threshold before they are removed. In the meantime, the acute symptoms can be controlled conservatively with antibiotics and analgesics.

Why thirty-two teeth?

The current dogma is teeth for life, however, for many patients this is unrealistic. In the caries or periodontally challenged dentition it would be a better option to consider the Reduced Dental Arch model and settle for, say, intact arches of twenty-four opposing teeth. This reduced enamel and dentine volume is more easily managed and can last a lifetime.

A further rationalisation for this approach is the Evolutionary Biology model. This model suggests that the current volume of enamel and dentine in thirty-two teeth is in excess of the requirement for contemporary dental needs. In the feral state abrasion and thegosis consume a great deal of tooth tissue. When the third molars erupt they provide the volume of enamel and dentine lost. In a contemporary dentition the abrasive wear (both occlusal and interproximal) does not occur and second and third molars provide an excess of tooth tissue volume. What is more, in some individuals the extra tooth tissue puts them at risk of infection and compromised function. On this basis, the Reduced Dental Arch model is a rational recommendation for some patients. (This is of course one of the arguments used in orthodontics for premolar extractions. It might make better sense to remove the second molars and juggle the remaining twenty teeth into position. Later, worry about the third molars.)

 

In summary, especially within Hospital Dentistry, there is a challenge to rationalise treatments. In many situations the current surgical management of dental disease is inappropriate and it is time for a rethink.

 

For a full reference list that supports the philosophy and opinions expressed here please contact the author.

Acknowledgment:

I would like to thank Ms Lisa Newick from Number 8 Enterprises and WEBcards for helping in the preparation and development of the Hospital Dental website and in the crafting the presentation of this paper at the Hospital Dental Surgeons Association Conference in Christchurch.


 Hospital Dental Services
 Canterbury Health Limited 1999


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