Biomechanics of Rehabilitating
the Perioprosthetic Patient
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17]Moreover, McLeod et al. (1998) declare that the prognosis of teeth that are initially
characterized as doubtful, is not that precise as the prognosis of teeth which are initially
characterized as teeth with a bad prognosis. [18] The above-mentioned study concurs with
that of by Fardal et al. (2004). These results are to confirm those largeretrospective studies
which report a very small rate of tooth loss in advanced periodontal patients after being under
follow-up programs for several years. Specifically, in a study of Hirschfeld and Wasserman
(1978), 600 treated periodontal patients, which were systematically re-examined for more
than 15 years, lost 4 teeth only in total, while in relative studies a very small rate of tooth loss
in periodontal patients during a long period of reexamining is referred. [19, 20, 21, 22, 23]
Wilson et al. (1987), in a comparative study of tooth loss during the period of more than 5
years in treated periodontal patients, which had systematically followed the program of
supportive therapy and in patients who failed to follow that program, point out that the
highest tooth loss occurred in patients that didn‘t follow the program. [24] Certainly, it is
mentioned in literature that the compliance of patients to the program of re-examination is not
correlated with a tooth loss in patients which suffer from a moderate or an initial
periodontitis. [25, 26] To an extent at which there are always doubts with regard to the
relativity of the above-mentioned results, these studies prove that the prognosis is a dynamic
procedure which is constantly being altered, precisely because the clinical parameters used
for the tooth survival are being affected by the periodontal treatment or by the additional
supportive treatment.[27] However, although there are some parameters which can be
eliminated very easily (bleeding during an examination, residual periodontal pockets) or
difficultly (smoking), there are some other parameters which are irreversible and concern the
tooth loss and the periodontal support loss. [28] In perioprosthetic patients, given the degree
of the previous osseous destruction, the progressively increasing mobility, the tooth loss and
the possibility of the disease to progress in a persistent or a recurrent type, the prognosis is of
crucial significance, since the treatment is accompanied by extendedcross-arch, fixed
restorations. [29, 30] However, despite the fact that the ability of the severely reduced
periodontal tissues to withstand those restorations had been questioned in the past, breaking
the Ante‘s law, there are studies which corroborate that, despite the loss of periodontal
support at a degree above 50%, the prognosis of those teeth is good. [31, 32] Moreover, the
results of Nyman and Lindhe (1979) and Nyman and Ericsson‘s studies (1982) prove that
limitations of the implementation of fixed restorations in abutment teeth with an extremely
reduced periodontium are attributed to technical and bio-mechanical problems in relation to
the construction of restorations, rather than to the biological ability of the periodontium to
support them successively. Of course, this is applied on the condition that strict protocol of
preservation of the sub-therapeutic program is followed. [33] The position of abutment teeth,
the presence of endodontic treatment, the restoration type and the type of the opposite dental
barrier had been implicated as factors aggravating the prognosis in perioprosthetic patient.
[34] However, results of clinical studies prove the good, for the time period over than 5 years,
prognosis of teeth with a healthy but extremely reduced periodontium as abutments of
extensive fixed prosthetic restorations (cross-arch splinting with or without the use of
cantilevers), decoherencing the restoration type and the tooth position with the prognosis. [35,
36, 37]