Endodoncia - Artículo - Methods Of Filling Root Canals: Principles And Practices - John Whitworth

Endodontic Topics 2005, 12, 2–24
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Copyright r Blackwell Munksgaard
ENDODONTIC TOPICS 2005
1601-1538

Methods of filling root canals:
principles and practices
JOHN WHITWORTH

Contemporary research points to infection control as the key determinant of endodontic success. While
epidemiological surveys indicate that success is most likely in teeth which have beendensely root-filled to within
2 mm of root-end, it is unclear whether the root canal filling itself is a key determinant of outcome. It is also unclear
how different materials and methods employed in achieving a ‘satisfactory’ root filling may impact on outcome.
This article provides an overview of current principles and practices in root canal filling and strives to untangle the
limited and oftencontradictory research of relevance to clinical practice and performance.

Introduction
Successful root canal treatment depends critically on
controlling pulp-space infection. In evaluating root
canal-treated teeth, it is unusual for external assessors
to have full information on the methods used and the
detail of infection-controlling steps. Attention therefore tends to focus on aspects oftreatment which can
be readily identified and measured, such as the radiographic nature, length and density of root fillings, with
the assumption that these are good proxy markers of
the overall package of infection-managing care. It is not
surprising that the majority of epidemiological surveys
in endodontics have focused on radiographic appearances alone (1), despite our recognized limitations inradiographic interpretation (2, 3), and acceptance that
the radiographic ‘white lines’ reveal only limited
information.
The classic ‘Washington study’ (4), although never
published in a peer-reviewed journal, set the tone by
observing that 58.66% of endodontic failures were
caused by incomplete obturation. Other well-established undergraduate textbooks have emphasized that
‘lack ofadequate seal is the principal cause of
endodontic failure’ (5), positions based on the best
clinical scientific evidence at the time.
Contemporary research points to cleaning and
shaping of the root canal as the single most important
factor in preventing and treating endodontic diseases
(6), and it is difficult to endow root canal filling with

2

the same primary importance. But to take suchviews
too rigidly, and to use reports of periapical healing
without definitive root filling as evidence that root
canal filling is unnecessary (7–10) is to miss the
important role it may play in securing short- and
long-term health (11, 12).
In technical terms, we anticipate that ‘success’ will be
associated with root canals (prepared and) densely filled
to within 2 mm of radiographic root end(1, 13).
However, the body of high-quality clinical research on
which such conclusions are founded is limited (14).
Even less clear is whether a technically ‘satisfactory’
root canal treatment will deliver health regardless of the
materials and methods, or whether some are inherently
‘better’ than others in terms of predictability, safety,
consistency, healing, and tooth longevity.Commercial pressures and glossy advertising have
never been more prominent, but the debates are not
new. As early as 1973, Brayton et al. (15) noted that
‘Many techniques have been advocated for filling root
canals. Controversies and disputes have arisen, dividing
practitioners into different schools of thought. To date,
there is still very little evidence other than clinical
impression to supportor deny any particular technique.’
As no single approach can unequivocally boast superior
evidence of healing success (13), decisions may be based
on such factors as speed, simplicity, economics, or ‘how it
feels in my hands.’ For some, there may be other issues at
stake, such as the desire to keep ‘up to date,’ to
demonstrate ‘mastery,’ to keep ahead of referring

Methods of filling root...