Coll. Antropol. 33 (2009) 4: 1349–1352
Original scientific paper
Changes of Alveolar Bone Density Around the
Abutment Teeth in Patients Wearing Removable
Partial Dentures Depending on Kennedy
Classification
Daniela Kova~evi} Pavi~i}
1
, Zdravko Deli}
1
, Vlatka Lajnert
1
, Vesna Fugo{i}
1
, Sun~ana Simoni}
Kocijan
1
and Dino Bukovi}
2
1
Department of Prosthodontics, School of Dental Medicine, University of Rijeka, Rijeka, Croatia
2
Department of Prosthodontics, School of Dental Medicine, University of Zagreb, Zagreb, Croatia
ABSTRACT
The aim was to study the influence of Kennedy classification on alveolar bone density changes around the abutment
teeth of removable partial denture (RPD) clasp and rests. A total of 50 examinees of both gender wearing RPDs were in
-
cluded in the study. Changes of bone density around the abutment teeth were determined by an intraoral microden-
sitometry method. Standard retroalveolar radiographs were obtained twice: the first one at the RPD delivery and the sec-
ond one after a period of 3 month of denture wearing. The copper stepwedge consisting of 5 steps (0.1–0.1 mm) was
attached to the radiograph prior to exposure in order to calibrate it. Seven regions of interest (ROI) in different position
close to the root of the abutment tooth were selected on each radiograph, all 10 pixels in size. Grey levels of each ROI were
measured and were converted into equivalents of the copper stepwedge thickness using the third degree polynomial in or-
der to compare the difference of bone density between the two radiographs. The results indicated that Kennedy classifica-
tion had no significant influence on the change of bone density in RPD patients during first 3 month of RPD wearing
(ANOVA: p>0.05).
Key words: alveolar bone, intraoral microdensitometry, retroalveolar radiography, removable partial denture, Ken-
nedy classification
Introduction
The reduction of alveolar bone density is an individ
-
ual process that depends on many sistemic (age, gender,
hormonal disturbancies, osteoporosis, etc.)
1–8
and local
factors (oral hygiene, masticatory stress, well planned
construction of RPD, etc.)
9,10
. All the examined subjects
wearing a RPD have a greater possibility of alveolar bone
resorption due to a greater stress to the abutment teeth
and the denture bearing area. It is well known that
occlusal rests distribute masticatory forces on the abut
-
ment teeth and further through the periodontal appara
-
tus to the alveolar bone
11
. During mouth opening, clasps
prevent RPD to dislodge from the denture bearing area
thus transmitting forces to tha abutment teeth in obli
-
que directions. The forces that affect the abutment teeth
in RPDs are different than in eugnatic natural dentition.
It is to be expected that bone apposition would occur
in cases of higher forces directed axially to the tooth
rooth
12
. In that case apposition of cement and alveolar
bone, i.e. greater bone density and specific bone trabe
-
cules are to be expected
13
. On the contrary, other forces
(such as the action of the retentive clasp) lead to the
stress of periodontal ligament. Such forces may exceed
the individual tolerance level leading to the reduction of
alveolar bone density. Literature suggests that some non
-
phisiological components of any of the RPDs can not be
completely avoided
14–16
. It has also been proven that ev
-
ery overload of the abutment tooth and surrounding al
-
veolar bone, as well as poor retention and stability of the
RPD lead to an increase in alveolar bone resorption
10
.In
different Kennedy classification of the edentulous areas
1349
Received for publication May 20, 2009.
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