Operative dentistry aje qualtrough, jd satterthwaite la morrow, pa brunton

PRESERVATIVE MANAGEMENT
Over recent years the dental profession has shifted towards prac-
tising preventive dentistry and adopting more conservative and
tooth-preserving procedures. Such progression is considered to be a
response to the decline in the level of dental caries and increased con-
sumer demands with regards to comfort of treatment and advances in
materials science. This shift in caries management, based on rational
clinical and scientific principles, will no doubt continue over the com-
ing decades
1
.
PRINCIPLES OF OPERATIVE INTERVENTION
Modern cavity preparation and design and the evolution thereof 
cannot, or perhaps should not, be considered without reference to 
G.V. Black. Black’s text A Work on Operative Dentistry in 1908
2
was the
first to prescribe a systematic method of cavity preparation and the
‘ideal’ cavity form. These features relate to the instruments available
at the time (slowly rotating burs with poor cutting efficiency and 
chisels), caries incidence and pattern, as well as restorative materials
available. Although modifications to the classical cavity forms and
principles to achieve these were suggested in the early 1900s, these
principles remained appropriate and largely unchallenged for a
period of over 50 years. The basic shape, and some of the ideals, of
Black’s cavities have been popular until recent times and indeed to a
degree are still prevalent.
The last 35 years have seen tremendous advances in dentistry, in
particular related to tooth-coloured restorative materials and in the
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bonding of restorative materials to tooth tissue. Such developments
have brought about a re-evaluation of Black’s principles and, further-
more, a move away from Black’s classification of carious lesions and
prescribed preparation form. Carious lesions are best described by 
the site in which they occur and the size of lesion, an approach taken
by Mount and Hume
3
in their proposal for a new classification of 
cavities. Many of the modifications have been made on an empirical
basis, with scientific evaluation and suggestions more prevalent in the
latter part of the last century (Table 2.1).
In contrast to Black’s principles of cavity preparation, which
included the establishment of outline form including extension for
prevention, the development of resistance and retention form, creation
of convenience form, the treatment of residual caries, the finishing of
cavity margins and cavity toilet, now the general principles of tooth
preparation are determined by:
• The nature and extent of the lesion.
• The quantity and quality of the tooth tissue remaining following
preparation.
• Functional load.
• The nature and properties of the restorative system to be used.
In general the minimum amount of tooth substance should be
removed to ensure appropriate access and the placement of the
required restoration. With developments in the range and properties
of the materials available for the restoration of teeth, it is now possible
to consider the preparation of teeth as an exercise in damage limita-
tion, with due consideration of both the macroscopic and microscopic
features of the biophysical environment into which it is intended 
to introduce a restoration. This concept was neatly described by