IMPLANT THERAPY DECISION-MAKING FOR ENDODONTICALLY INVOLVED DENTITION
Figure 1 Factors influencing the decision to save or extract an endodontically affected tooth
Material and methods
Screening process
An electronic literature search for relevant articles
published in English was conducted in the
PubMed database from January 1990 to August
2013 by three examiners (AM, FS and CG). The
key words used in the search included “dental
implant”, “endodontic lesion”, “endosseous
implant”, “periapical lesion”, and “root canal
treatment”. Boolean operators, “OR” and “AND”,
were used to combine the literature searches.
Due to the heterogeneity among articles and
lack of controlled studies, a narrative review was
performed instead of a systematic review.
Factors influencing the decision to save or
extract an endodontically affected tooth (Fig.1)
Periodontal stability is a significant factor that
influences tooth retention. A prognostication
system proposes using the likelihood of achieving
periodontal stability as the key consideration
when assigning teeth to 4 prognosis categories,
which are favorable, questionable, unfavorable
or hopeless (Kwok and Caton, 2007). Generally, a
tooth with a hopeless prognosis will be extracted
and if tooth replacement is needed, a dental
implant is a viable treatment option. On the other
hand, a tooth with a favorable prognosis can be
retained over time as long as proper periodontal
treatment and maintenance are performed.
Therefore, endodontic treatment should be
attempted if the tooth is restorable.
Restorability of an endodontically involved tooth
is influenced by several factors. One key factor is
STOMA.EDUJ (2015) 2 (1)
the amount of remaining sound tooth structure.
A minimum axial wall height of 3mm for anterior
teeth and premolars and 4mm for molars is
recommended for retention of the crown (9). There
should also be 1mm of sound dentine thickness
with 2mm of sound tooth structure between the
core material and the restorative margin (10).
This provides the ferrule effect, which braces the
tooth and is crucial in resisting dislodgement of
the prosthesis and tooth fracture, thus providing
a better long-term prognosis of the tooth (11). If
360º ferrule effect cannot be obtained, a partial
ferrule can be considered (11, 12). It is important
to have adequate ferrule at sites where lateral
forces are exerted during functional loading. For
example, in a typical Class I occlusion, palatal
ferrule is needed for maxillary anterior teeth,
buccal and palatal ferrule is needed for maxillary
premolars and molars and buccal ferrule is needed
for mandibular anterior teeth and premolars.
The biologic width, defined as the soft tissue
attachment coronal to the alveolar bone crest (13)
is generally accepted to be 2.04mm (14). Violation
of the biologic width, e.g. placement of the
restorative margin close to the bone crest, results
in chronic gingival inflammation (15), clinical
attachment loss (16), bone loss (17), gingival
recession and deeper pockets (18). Therefore,
adequate biologic width must be maintained for
periodontal health around a restoration.
Crown lengthening or orthodontic extrusion can
be performed to gain additional tooth height for
the ferrule effect or to prevent violation of biologic
width. However, it is important to avoid exposing
the furcation, as it would increase the susceptibility
of the tooth to progression of periodontal disease
57